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358 terms

MCAT Organic Chem

Combination of terms
STUDY
PLAY
________s, also known as Paraffins, are chemical compounds that consist only of the elements carbon and hydrogen linked together exclusively by single bonds.
Alkane
A ________, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond.
Alkene
A ________ is any organic compound in which a hydroxyl group (-OH) is bound to a carbon atom of an alkyl or substituted alkyl group
Alcohol
A ________ is either the functional group characterized by a carbonyl group linked to two other carbon atoms or a chemical compound that contains this functional group.
Ketone
________ in chemistry stands for a molecule consisting of an oxygen atom and a hydrogen atom connected by a covalent bond. When the oxygen atom is linked to a larger molecule the hydroxyl group is a functional group.
Hydroxyl
________ is the substituent form of the alkane propane.
Propyl
________ is a four-carbon alkyl substituent derived from either of the two isomers of the alkane called butane.
Butyl
A ________ is an organic compound containing a terminal carbonyl group.
Aldehyde
Traditionally known as acetylenes or the acetylene series, the ________s are hydrocarbons that have at least one triple bond between two carbon atoms.
Alkyne
________ acids are organic acids characterized by the presence of a carboxyl group.
Carboxylic
________ involves the study of the relative spatial arrangement of atoms within molecules.
Stereochemistry
The term ________ is used to describe an object that is non-superimposable on its mirror image.
Chiral
________-trans isomerism is a form of stereoisomerism describing the orientation of functional groups typically around double bonds which cannot rotate.
Cis
________ effects arise from the fact that if atoms are brought too close together, there is an associated cost in energy due to overlapping electron clouds.
Steric
________s are stereoisomers that are nonsuperimposable complete mirror images of each other.
Enantiomer
A ________ mixture is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule.
Racemic
________s are stereoisomers that are not enantiomers.
Diastereomer
Optical rotation or optical ________ is the rotation of linearly polarized light as it travels through certain materials.
Activity
A ________ compound is a chemical compound with molecules that contain 2 or more stereocenters but which is optically achiral because it contains an internal plane of symmetry.
Meso
A ________ projection visualizes chemical conformations of a carbon-carbon chemical bond from front to back, with the front carbon represented by a dot and the back carbon as a circle.
Newman
A ________ conformation is a chemical conformation that exists in any open chain single chemical bond connecting two sp3 hybridised atoms as a conformational energy minimum.
Staggered
A ________ conformation is a chemical conformation that exists in any open chain single chemical bond connecting two sp3 hybridised atoms as a conformational energy maximum.
Eclipsed
A ________ is any atom in a molecule bearing groups such that an interchanging of any two groups leads to a stereoisomer.
Stereocenter
________ isomerism is a form of stereoisomerism involving molecules with the same structural formula existing as different conformers due to atoms rotating about a bond.
Conformational
Van der Waals ________ results from van der Waals repulsion when two substituents in a molecule approach each other with a distance less than the sum of their van der Waals radii.
Strain
________ refers to the physical property of a molecule that is repelled from a mass of water
Hydrophobicity
A ________ is an organic compound consisting entirely of hydrogen and carbon.
Hydrocarbon
________ refers to a physical property of a molecule that can transiently bond with water through hydrogen bonding.
Hydrophilicity
________ is a term in chemistry that refers to the property of liquids to mix, forming a homogeneous solution.
Miscibility
________ refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene.
Lipophilicity
________ compounds are organic compounds in which carbon atoms are joined together in straight or branched chains or in rings, that can be either saturated or unsaturated, but not aromatic.
Aliphatic
________ is a common name for the group of alkane hydrocarbons.
Paraffin
________ is a measure of the speed at which a substance turns into a vapor from a solid or liquid state.
Volatility
________ organic compounds (VOCs) are organic chemical compounds that have high enough vapour pressures under normal conditions to significantly vaporize and enter the atmosphere.
Volatile
________ is a term describing a chemical compound possessing both hydrophilic and hydrophobic properties.
Amphiphile
A ________ or distribution coefficient is the ratio of concentrations of a compound in the two phases of a mixture of two immiscible solvents at equilibrium.
Partition
A ________ solvent is a solvent that carries a hydrogen bond between an oxygen as in a hydroxyl group or a nitrogen as in an amine group.
Protic
Liquid-liquid or solvent ________, also known as partitioning, is a method to separate compounds based on their relative solubilities in two different immiscible liquids, usually water and an organic solvent.
Extraction
________ is the ability of a substance to attract water molecules from the surrounding environment through either absorption or adsorption.
Hygroscopy
A ________ liquid is a mixture consisting of more than two immiscible liquid phases.
Multiphasic
Relative ________ is a measure of the vapor pressure differences of the components in a liquid mixture of chemicals.
Volatility
________s are amphiphilic molecules that have hydrophilic groups at both ends of a sufficiently long hydrophobic hydrocarbon chain.
Bolaamphiphile
________ is a term which literally means fat rejection and describes compounds which are not soluble in lipids or other non-polar solvents.
Lipophobicity
________-Huggins solution theory is a mathematical model of the thermodynamics of polymer solutions which takes account of the great dissimilarity in molecular sizes in adapting the usual expression for the entropy of mixing.
Flory
A material is called ________ if it forms liquid crystal phases because of the addition of a solvent.
Lyotropic
________ acid, also known as ethanoic acid, is an organic chemical compound best recognized for giving vinegar its sour taste and pungent smell.
Acetic
________ acids are organic acids characterized by the presence of a carboxyl group.
Carboxylic
Amines and nitrogen-containing heterocyclic compounds are organic ________s.
Base
________s are organic compounds and a type of functional group that contain nitrogen as the key atom. Structurally they resemble ammonia, wherein one or more hydrogen atoms are replaced by alkyl and aryl groups.
Amine
Has four groups bonded to it; R side chain, amino group, carboxyl group, and hydrogen , refers to the first carbon that attaches to a functional group
alpha carbon
Acidity in aldehydes & ketones may occur with this atom
alpha hydrogen
describes the exact spatial arrangement of groups of atoms independent of other molecules.
absolute configuration
all peaks are assigned abundances as percentages of the base peak. abundance of 10 means that peak is 10% as high as the base peak
abundances
any organic compound formed by adding alcohol molecules to aldehyde molecules
acetal
pH values below 7
acidities
R-CO-Cl, inorganic acid chlorides like SOCl₂, PCl₃, and PCl₅ each react with carboxylic acids by nucleophlic substitution to form ____ _____.
are Bronsted-Lowry acids.
acyl chlorides
organic compounds containing hydroxyl groups , ROH
alcohols
any group or radical of the form RCO- where R is an organic group
acyl group
R-C=O-H , Carbon atom of the carbonyl group is bonded to another carbon and one hydrogen atom
aldehydes
-always results in beta hydroxy carbonyl group
-requires the presence of alpha hydrogens , What is the name of the reaction of two aldehydes or an aldehyde and a ketone?
aldol condensation
1) Alanine
2) Proline
3) Valine
4) Glycine (Only non-chiral AA)
5) Leucine
6) IsoIeucine
aliphatic acids
a hydrocarbon containing only single covalent bonds, CnH2n+2
alkanes
any unsaturated aliphatic hydrocarbon, consists of at least one carbon to carbon double bond
alkene
a salt formed by replacing the hydroxyl ion of an alcohol with a metal, a compound derived from an alcohol and containing a metal atom bonded to an oxygen atom
alkoxide
if an alcohol is used instead of water in the creation of an alcohol from a alkene the process is known as alkoxy
mercuration/demercuration
groups of atoms that form when one hydrogen atom is removed from an alkane molecule; alkanes with a hydrogen atom removed
alkyl groups
any organic compound containing the group -CONH2
amide
...organic compounds which contain and are often actually based on one or more atoms of nitrogen. Structurally _______resemble ammonia in that the nitrogen can bond up to three hydrogens, but ________also have additional properties based on their carbon connectivity.
amine
A molecule that has both a hydrophilic region and a hydrophobic region.
amphipathic
oxides that contain no water, Consisting of an internal Oxygen in between two Carbons each with a double bond to another Oxygen: -(C=O)-O-(C=O)
anhydrides
monosaccharides differing only in their configuration at the hemiacetal/hemiketal carbon in a pyranose ring (can be alpha or beta)
anomers
An addition reaction in which the two added substituents add to opposite sides of the molecule
anti-addition
the acid or electrophile(Br-) adds to the least subsituted carbon while the hydrogen adds to the carbon with most hydrogens
anti-markovnikov
(chemistry) of or relating to or containing one or more benzene rings
aromatic
a closed chain of 6 carbon atoms with hydrogen atoms attached , consists of 5 or 6 carbons joined together in a cyclic structure with alternating double and single bonds
benzene ring
Hydrogens whose bonds lie approximately perpendicular to the plane of a cycloalkane ring
axial hydrogens
C6H6 , the primary aromatic hydrocarbon
benzene
a light strong brittle gray toxic bivalent metallic element
beryllium
rule that the most substitituted alkene is the major product, in the dehydration of an alcohol, hydrogen is removed from the carbon that already has the smaller number of hydrogen atoms to form an alkene
saytzeff rule
an elimination in which the two atoms lost are a hydrogen atom and a halogen atom
dehydrohalogenation
because acetals and ketals are unreactive towards bases, they are often used as _____ ______
blocking groups
the energy required to break the bond between two covalently bonded atoms
bond dissociation energy
the energy required to break a chemical bond and form neutral isolated atoms
bond energy
3 >2> 1> +CH3 More carbons nearby =more stable, Carbocations are classifided by the number of R gourps bonded to the charged carbon atom: Primary (1), Secondary (2), tertiary (3).
As the number of R groups increases, carboncation stability increases.
Carbocation stability is determined by inductive effects and hyperconjugation effects.
carbocation stability
C=O, a carbon atom joined to an oxygen atom by a double bond-ketones and aldehydes
carbonyl
R-COOH, an organic compound containing a carboxyl group
carboxylic acids
the difference between the position of absorption of TMS and that of a particular proton.
chemical shift
an atom with substituents arranged so that the molecule is not superimposable on its mirror image, carbon atom bonded to four different groups
chiral center
A property of a compound to exist in both left and right forms; occurs whenever a compound contains an asymmetric carbon
chirality
A physical process used to determine what type of substances have been mixed together
chromotography
The isomer in which the substituents are on the same side of the double bond.
cis
Fill a buret and filter your mixture through particles in the buret into a beaker
column chromotography
a rapid reaction between oxygen and fuel that produces thermal energy
combustion
stereoisomers that differ by rotation about one or more single bonds, usually represented using newmman projections.
conformational isomer
structures that differ only by rotations about single bonds. introvert at room temperature; thus, they are not different compounds and not true isomers
conformers
occurs when there is a weak base and a carbonyl group; this is where equilibrium goes towards.
conjugate addition
a covalent bond in which one atom contributes both bonding electrons
coordinate covalent bond
are strain free due to reduction in eclipsing interactions and the chair/boat conformations; each carbon in this is bonded to a hydrogen in teh axial position and another in teh equatorial position; axial hydrogens alternate their position (up and down) across an imaginary internal plane for each adjacent carbon
cyclohexane
a crystalline amino acid found in proteins (especially keratin)
cystine
5 different orbitals shaped like clover leaves and max electrons is 10
d orbital
The unit used to express dipole moments.
debye
the process of removing a carboxyl group from a chemical compound (usually replacing it with hydrogen)
decarboxylation
the electrons involved in metallic bonding that are free to move easily from one atom to the next throughout the metal and are not attached to a particular atom
delocalized electrons
stereoisomers that are not mirror images of each other
diastereomers
instrument that records numbers which correspond to the rise in the line.
digital trace
a compound whose molecules are composed of two identical monomers
dimer
Product of the amount of partial charge at either end of a molecule's dipole multiplied by the distance between them, given equation "p=qd". P is the dipole moment, q is the partial charge, and d is the distance separating the dipole
dipole moment
the process of purifying a liquid by boiling it and condensing its vapors
distillation
Lipids that exert complex control over many bodily systems, mainly in inflammation or immunity, and as messengers in the central nervous system.
eicosanoids
tend to increase shielding and increase the required field strength for resonance., activate the ring and direct any substituents to the ortho and para positions, includes the groups: -O, -OH, -NR2, -OR, -R
electron donating groups
the reduction of the attractive force between a positively charged nucleus and its outermost electrons due to the cancellation of some of the positive charge by the negative charges of the inner electrons
electron shielding
in the R position, deactivates the ring and directs new subtituents to the meta position, Strong: NO₂, Halogens
Moderate: Carbonyls (Ketone, Aldehyde, Ester, C.A.), Nitrile, Sulfonate
Weak: -X
electron withdrawing group
A type of addition reaction in which an electrophile is attracted to an electron-rich centre or atom, where it accepts a pair of electrons to form a new covalent bond.
electrophilic addition
An amino group attached to a carbon in a carbon-carbon double bond.
enamines
the ratio of pure enantiomer to racemic mixture. optical purity equals ___ ____ for any mixture of enantiomers
enantiomeric purity
either one of a pair of compounds (crystals or molecules) that are mirror images on each other but are not identical
enantiomer
Can change from one polymorphism form to another and is reversible by varying temperature and pressure
enantiotropic
- a resonance-stabilized carbanion
- negatively charged & nucleophilic
note: strong base
enolate ion
opposite
entgegen
Isomers that differ in configuration at only one of several chiral centers, Monosaccharides which differ in configuration about a single ANOMERIC carbon
epimer
An ether in which the oxygen is incorporated into a three-membered ring , (R₂C-CR₂)-O
epoxide
formed by reaction between an acid and an alcohol with elimination of water, contains an internal O=C-O- group
ester
R-O-R
ether
the process of obtaining something from a mixture or compound by chemical or physical or mechanical means
extraction
Charge assigned to an atom in a molecule or polyatmic ion, calculated by (# valence electrons) - (# 1/2 bonding electrons) - (# nonbonding electrons). Molecules containing atoms with lower formal charges tend to be more stable than those with higher formal charges.
formal charge
Uses a machine that vaporizes a liquid to a gas then passes through coils and the speed with which it moves lets you know its molecular weight
gas chromotography
Molecule with two hydroxyl groups an the same carbon
geminal diol
two ether groups that share a carbon (with two R groups), R'O(CR2)OR'
ketal
Lowest Unoccupied Molecular Orbital
lumo
a compound containing a halogen atom and a hydroxyl group on adjacent carbons; those containing Br and OH are bromohydrins, and those containing Cl and OH are chlorohydrins
halohydrin
the heat of reaction for the complete burning of one mole of a substance
heat of combustion
an organic compound usually formed as an intermediate product in the preparation of acetals from aldehydes or ketones
hemiacetal
Highest Occupied Molecular Orbital
HOMO
For a molecule to be aromatic it must have 4n+2 pi electrons
huckels rule
Anti-markovnikov addition, syn addition, replacement of BR2 with other functionalities, quasicyclic intermediate
hydroboration
a crystalline amino acid obtained from gelatin or collagen
hydroxyproline
Compound with a carbon double-bonded to nitrogen (C=N).
imine
the number of pairs of hydrogens a compound requires in order to become a saturated alkane
index of hydrogen deficiency
when a very polar molecule comes in contact with a nonpolar molecule, it can cause the nonpolar molecule to become a temporary dipole.
induced dipoles
measures molecular vibrations that can be seen as bond stretching, bending, or combinations.
infrared spectroscopy
line drawn above the peaks that rises each time it goes over a peak. the rise of the ___ ____ is in proportion to the number of chemically equivalent hydrogens in the peak beneath it
integral trace
The atom or group of atoms that leave during a substitution or elimination; these are usually stable atoms, weak bases.
leaving group
have 2 symetrical chiral centers, therefore, they are achiral
meso compounds
hydrocarbon with a C-triple bond-N
nitrile
resonance of protons to radiation in a magnetic field
NMR
a molecule must have this to be able to be studied using NMR. common nuclei are H, C, F O N P
nuclear spin
A species that tends to donate electrons to another atom. They are attracted to positive charge, a nucleus, (protons and neutrons). In protic solvents and situations with different attacking atoms, its strength correlates to size. In aprotic solvents with the same attacking atom, its strength corresponds to basicity.
nucleophile
A type of substitution reaction in which a nucleophile is attracted to an electron-deficient centre or atom, where it donates a pair of electrons to form a new covalent bond.
nucleophilic substitution
the number of degrees through which a compound rotates the plane of polarized light
observed rotation
the specific rotation of a mixture of enantiomers divided by the specifec rotation of the enantiomerically pure substance.
optical purity
The electron acceptor in a redox reaction.
oxidizing agent
three membered ring ether
oxirane
The addition of water to alkenes. This gives the markovnikov addition product of an alcohol (-OH attached to the more highly substituted carbon, H to the less substituted carbon). Uses Hg[OAc] in THF solvent. This forms a mercurinium ion. Then the nucleophilic addition of H2O forms a organomercury compound. Last the addition of NaBH4 removes the mercury leaving an alcohol. If added to a unsymetrical alkene it gives syn-sterochemestry. Meaning both boron and hydrogen add to the same face of the double bond.
oxymercuration
cleaves double bond in half, it only oxidizes the carbon to an aldehyde under reducing conditions. if ozidizing make same product as KMNO4
ozonolysis
a bond that is formed when parallel orbitals overlap to share electrons.
pi bond
A solvent that is not a proton donor. An aprotic molecule does not bear a transferable proton.
aprotic solvent
A solvent that has a hydrogen atom bound to an oxygen as in a hydroxyl group or a nitrogen as in an amine group.
protic solvent
refers to a hydrogen atom attached to an electronegative atom. For our purposes that electronegative atom is almost exclusively oxygen or nitrogen. Will cause an Sn1 reaction.
polar protic solvent
good solvents for Sn2 reactions because they allow the nucleophile to dissolve without solvating it (forming hydrogens bonds that require energy to break when acting as a nucleophile) (DMF)
polar aprotic solvent
hormonelike modified fatty acid produced by a wide range of cells; generally affects only nearby cells and tissues
prostaglandin
A mixture that contains equal amounts of the (+) and (-) enantiomers. Racemic mixtures are not optically active.
racemic mixture
In chemistry, a mixture that has equal amounts of left- and right-handed enantiomers of a chiral molecule. (no optical activity)
racemic
the slowest elementary step which is the limit for the rate of the other steps
rate determining step
an atom or group of atoms with at least one unpaired electron
radical
relative front; number used to determine which pigment has been separated on the paper by dividing the movement of the pigment by the movement of the solvent.
rf factor
difference in energy btwn a resonance hybrid and the most stable of its hypothetical contributing structures
resonance energy
a bond formed when two atomic orbitals combine to form a molecular orbital that is symmetrical around the axis connecting the two atomic nuclei
sigma bond
a chemical reaction in which an ester is heated with an alkali (especially the alkaline hydrolysis of a fat or oil to make soap)
saponification
The condensation of an amine with a carbonyl forms this. It acts as an electron sink that stabilizes negative charge on the adjacent carbon.
schiff base
The mechanism that forms a carbocation in the rate-determining step is the _____ mechanism., tertiary halogenoalkanes react in this method; first the halogen breaks off then the nucleophile attaches onto the positively charged carbon
SN1
Primary halogenoalkanes follow the _______ mechanism of nucleophilic substitution., The mechanism that forms a transition state with a high activation energy is the _____ mechanism.
SN2
a nucleophilic substitution or elimination where the solvent serves as the attacking reagent. literally means "cleavage by the solvent"
solvolysis
The rotation of plane-polarized light induced by a solution of a molecule of concentration 1 g/mL in a tube 10 cm long.
specific rotation
An interaction in which nuclear spins of adj. atoms influence each other and lead to the splitting of NMR signals.
spin spin coupling
when non-equivalent hydrogens are not separated by at least one carbon or oxygen atom this happens
spin spin splitting
Interference by bulky groups that slow a reaction or prevent it from occurring.
steric hindrance
Addition reaction in which the two added substituents add to the same side of the molecule
syn addition
Two isomers which differ only in the placement of a proton. R-C(=O)-R <--> R-C(-OH)=R.
tautomer
Alkene + X2
N/A, Anti
vic dihalide
obtained by passing ultraviolet light through a sample and absorbance is plotted against wavelength. the absorbance is caused by electronic transition between orbitals
uv spectroscopy
internal standard for frequencies on an NMR spectra
tetramethylsilane
procedure to analyze a mixture by seperating constituents based on selective adsorbtion based on polarity differences
TLC
The two-electron bond, which is illustrated
by the carbon-hydrogen bonds in methane or ethane and the carbon-carbon
bond in ethane, is called a
single bond
H:C:::C:H
ethyne
CH3CH3
ethane
CH2CH2
ethene
CHCH
ethyne
CH20
methanal
(formaldehyde)
CH3C02H
ethanoic acid
HCN
methanenitrile
A process carried out on petroleum distillates at high temperature and pressure, ________ yields lower carbon number product, probably by means of a radical (homeolytic) mechanism. The thermodynamics are dominated by the entropy change rather than the enthalpy change, especially if the volume is kept constant.
Thermal Cracking - Pyrolysis
Because of the relative stability of alkyl radical intermediates, selectivity in free radical halogenation favors tertiary over secondary over primary carbon radicals. Bromination, though, is more selective than chlorination, because the proton extraction step is more endothermic in bromination than chlorination. This follows from Hammond's postulate, which governs the correlation between proximity in energy and proximity in structure among transition states and intermediates. Halogenation is the classic illustration of Hammond's postulate. Because the activated complex prior to formation of the alkyl radical intermediate must have more radical character for bromination compared to chlorination, the effect of substitution in stabilizing radicals plays a greater roll with bromination leading to a higher degree of regioselectivity.
Free Radical Halogenation
are the simplest and least reactive hydrocarbon species containing only carbons and hydrogens. They are commercially very important, being the principal constituent of gasoline and lubricating oils and are extensively employed in organic chemistry;
Alkanes The distinguishing feature of an alkane, making it distinct from other compounds that also exclusively contain carbon and hydrogen, is its lack of unsaturation. That is to say, it contains no double or triple bonds, which are highly reactive in organic chemistry.
also called conformational isomers, or rotational isomers, are arrangements of the same molecule made transiently different by the rotation in space about one or more single bonds.

Other types of isomer can only be converted from one form to another by breaking bonds, but conformational isomers can be made simply by rotating bonds.
Conformers
drawings used to represent different positions of parts of molecules relative to each other in space. Remember that single bonds can rotate in space if not impeded. _______represent different positions of rotating molecule parts.
Newman projections
Different conformations have different potential energies. The staggered conformation is
at a lower potential energy than the eclipsed conformation, and is favored. In ethane, the barrier to rotation is approximately 25 kJ/mol, indicating that each pair of eclipsed hydrogens raises the energy by about 8 kJ/mol. This number also applies to other organic compounds which have hydrogen atoms at similar distances from each other. At very low temperatures all conformations revert to the stabler, lower energy staggered conformation.
have to do with size. Two bulky objects run into each other and invade each others space. If we replace one or more hydrogen atoms on the above Newman projections with a methyl or other group, the potential energy goes up especially for the eclipsed conformations.
Steric effects
represented as a ΔS, is a mathematical construct that represents disorder or probability. Natural systems want to find the lowest energy or organization possible, which translates to the highest __________.
Entropy
Alkanes react only very poorly with
ionic or other polar substances. The pKa values of all alkanes are above 50, and so they are practically inert to acids and bases.
are two molecules with the same molecular formula but different physical arrangements
Isomers
have their atoms arranged in a different order.
Constitutional isomers
are isomers which have the same pattern of bonding but with atoms arranged differently in space.
Stereoisomers
Stereoisomers are also known as geometric isomers but confusingly this latter term is often used to refer only to
'cis/trans isomers'.
two isomers which are mirror images of each other; also known as optical isomers due to the fact that two ___________will rotate plane-polarized light in equal, but opposite directions. Chirality is (yet) another term for .
enantiomerism
stereoisomers which are not enantiomers.
Diastereomers
Stereoisomerism can be caused by:
Stereocenters
if a carbon atom has four different groups attached to it, it will exhibit enantiomerism. Other causes of enantiomerism include helical structures.
Non-rotation of bonds
the C=C bond cannot rotate and is the most common cause of diastereomerism. Other causes are cyclic compounds and steric hindrance.
is the set of possible shapes a molecule can have by means of rotation about single bonds only.
Conformation
is the relative position of the atoms in a molecule that can be changed exclusively by cleaving and forming new chemical bonds.
Configuration
is the property of handedness. An object that is ________is an object that can not be superimposed on its mirror image.________ objects don't have a plane of symmetry.
chiral
A mixture of equal amounts of both enantiomers is said to be a
racemic mixture
Diastereomers seldom have the same physical properties. Sometimes, the stereocentres are themselves symmetrical. This causes the counterintuitive situation where two chiral centres may be present but no isomers result. Such compounds are called
meso compounds.
It is the symmetry of a molecule (or any other object) that determines whether it is chiral or not. Technically, a molecule is achiral (not chiral) if and only if
it has an axis of improper rotation; that is, an n-fold rotation (rotation by 360°/n) followed by a reflection in the plane perpendicular to this axis which maps the molecule onto itself.
There are 3 main conformations of Cyclohexane
the chair, the reverse chair and the boat. The chair conformations have no angular, torsional or steric strain. However the boat conformation does have steric strain, as the hydrogens at the high points on the front and back of the boat are slightly overlapping.
Different conformations of cyclohexane can react differently for certain reactions. For example, the E2 elimination reaction requires
that a halogen atom and a hydrogen atom be on adjacent carbons and coplanar from each other, or 180° (anti). In cyclohexanes with multiple substituents attached to its carbons, it's possible for the hydrogen and halogen to be on adjacent carbons, but never be coplanar, thus preventing the reaction from occurring.
are cyclic compounds that contain atoms other than carbon in their ring
Heterocyclic compounds
RCOX A group having alkyl or aryl group with a carbonyl group RCO-
Acyl group Acyl halide
A hydrocarbon containing atleast one carbonyl gp having one hydrogen attached to it.(>C=O)
Aldehyde
When two similar aldehydes are reacted with each other,a product having both aldehyde(>C=O) and alcohol(OH) group is formed.This reaction is called aldol reaction.
Aldol reaction
A molecule with two single bonded oxygens attached to the same carbon atom.
Acetal
A functional group with chemical formula -COCH3.
Acetyl
A group containing atleast two identical substituents.
Achiral
Hydrocarbon containing two carbonyl groups.Acyl group attached with carboxylate group.eg- RCOOCOR'
Acid anhydride
Acyl group with any halogen attached with carbon of carbonyl group.eg.- RCO-X(X=F,Cl,Br,I).
Acid halide
Any group which activate any molecule by increasing positive or negative charge on carbon atom.Mainly towards neucleophilic or electrophilic substitution reactions.
Activating group
The energy required to reactants to cross energy barrier to undergo any chemical change.denoted by Ea.
Activation energy
A group having alkyl or aryl group with a carbonyl group RCO-
Acyl group
A catalyst for hydrogenation and hydrogenolysis in organic synthesis. Also known as platinum dioxide
Adam's catalyst
A non-cyclic, non-aromatic, hydrocarbon chain (e.g. alkanes, alkenes, and alkynes)
Aliphatic
The conjugate base of an alcohol without the terminal H atom. For any alcohol R-OH, the corresponding alkoxide form is R-O-.
Alkoxide ion
A hydrocarbon having formula CnH2n+1
Alkyl
A hydrocarbon containing amnine group attached to acyl group. eg.- RCONH2
Amide
A chemical property in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone.
Aromacity
The bond parellel or anti parellel to axial coordinate passing center of gravity.
Axial bond
Dutt-Wormall reaction in which a diazonium salt reacts with a sulfonamide first to a diazoaminosulfinate and then on hydrolysis the azide and a sulfinic acid.
Azide synthesis
A compound containing two cyclic rings.
Bicylcoalkane
The acyl of benzoic acid, with structure C6H5CO-
Benzoyl Group
- A second order reaction where the concentration of two compounds determine the reaction rate.
Bimolecular reaction
A rule for assigning priorities to substituents off of carbon in a double-bond or in a chiral center.
Cahn-Ingold-Prelog priorities
A chemical reaction in which a carboxylic acid group is introduced in a substrate.
Carboxylation
The process of separating compounds such as a dye into its constituents
Chromatography
- A system of atoms covalently bonded with alternating single and multiple (e.g. double) bonds (e.g., C=C-C=C-C).
Conjugation
The ability of electrons to spread out among pi bonds to provide stabilization to electronically unstable areas of a molecule.
Delocalization
A term used to describe the left direction on NMR charts. A peak to the left of another peak is described as being downfield from the peak.
Downfield
Literally, electron lover. A positively or neutrally charged reagent that forms bonds by accepting electrons from a nucleophile. Elecrophiles are Lewis Acids.
Electrophile
A reaction where atoms and/or functional groups are removed from a reactant.
Elimination reaction
An alkene with a hydroxyl group affixed to one of the carbon atoms composing the double bond.
Enol
An inorganic or organic acid in which at least one -OH (hydroxyl) group is replaced by an -O-alkyl (alkoxy) group.
Ester
An organic compound which contains an ether group — an oxygen atom connected to two (substituted) alkyl or aryl groups — of general formula R-O-R'.
Ether
A reaction whose rate is determined by the concentration of only one of its reactants leading to a reaction rate equation of Rate = k[X]
First order reaction
Where bond breaks leaving each atom with one of the bonding electrons, producing two radicals.
Homolytic cleavage
A chemical reaction in which a hydroxyl group (OH-) and a hydrogen cation (an acidic proton) are added to the two carbon atoms bonded together in the carbon-carbon double bond which makes up an alkene functional group.
Hydration
A reaction adding BH3 or B2H6 or an alkylborane to an alkene to produce intermediate products consisting of 3 alkyl groups attached to a boron atom. This molecule is then used in other reactions, for example, to create an alcohol by reacting it with H2O2 in a basic solution.
Hydroboration
Addition of a hydrogen atoms to an alkene or alkane to produce a saturated product.
Hydrogenation
A chemical process that introduces one or more hydroxyl groups (-OH) into a compound (or radical) thereby oxidizing it.
Hydroxylation
The functional group characterized by a carbonyl group (O=C) linked to two other carbon atoms, or a chemical compound that contains a carbonyl group
Ketone
A reagent that accepts a pair of electrons form a covalent bond
Lewis acid
A reagent that forms covalent bonds by donating a pair of electrons
lewis base
Alkane
Chain of carbons connected by single bonds with hydrogen atoms attached.
Alkane nomenclature
Use the Greek root for the number of carbons followed by the ending, -ane
Ignored
di, tri, t, sec, n-
not ignored
iso, neo, cyclo
Alkene
contain carbon carbon double bonds. Use same root of alkane but end with "ene"
Vinyl
monosubstituted ethylene
allyl
propylenes attached to a backbone at the C-3 position. Meaning the double bond at end of the chain and single bonded carbon at rest
methylene
refers to the =CH2 group
Alkyne
carbon carbon triple bonds. Suffix-yne.
Acetylene
Common name for ethyne
y-root-en-x-yne
y = position of double bond, x is position of triple bond, root is the prefix representing the length of the principal carbon chain
Haloalkane
compounds with halogen
halogen
F, CL, Br, I
diol
two hydroxyl groups
vicinal
diols with hydroxyl group on adjacent carbon
geminal
diol with hydroxyl group on same carbon
ethers
functionality is specified by alkoxy-prefix. ROR
carbonyl
carbon double bonded to an oxygen
aldehyde
carbonyl located at the end of the chain named by replacing al with e. e.g. butanal
formaldehyde
name for mathanal
acetaldehyde
name for ethanal
propionaldehyde
name for propanal
ketone
carbonyl located in middle or somewhere in chane. Named with ONE
carboxylic acid
always receive number one. contain carbonyl and OH group, very oxidized. highest priority functional group.
amines
nitrogen containing compound, longest chain attached to nitrogen used in backbone. use e and replace with AMINE. if more complex molecule present, use prefix amino. IF additional group added, use N-
structural isomers
share molecular formula but have different chemical and physical properties
isomer
same molecular formula but different structure
stereoisomers
same chemical formula. same atomic connectivity . different in how atoms are arranged in space
geometric isomers
differ in position of substitutents attached to a double bond or cycloalkane. Cis or trans or e or z
chiral
object that is not superimposable upon mirror image
chiral center
carbon with four different substituents and lack a plane of symmetry
enantiomer
nonsuperimposable mirror image of chiral objects, a specific steroisomer.
achiral
three different substitutents often have plane of symmetry. and rotation of 180 will allow molecule to be superimposed on mirror image
configuration
spatial arrangement of the atoms or groups of a sterioisomer
relative configuration
configuration in relation to another chiral molecule. use it to determine if a molecule is an enantiomer, diastereomer, etc
absolute configuration
describes the exact spatial arrangement of groups of atoms independent of other molecules.
fischer projection
lowest priority group projects into the page
enantiomer
moleculse that have the opposite configuration at their one chiral center. or if multiple chiral centers, must have the opposite configuration at every one of their chiral centers to be enantiomers. identical physical properties and much of the same chemical properties. but differe in optical activity and how they react in a chiral environment
optical activity
if a compound is able to rotate plane polarized light.
specific rotation
a = observed rotation / concentration * length
racemic mixture
rotations cancel each other out therefore no optical activity
diastereomers
non mirror image of configurational isomers. cis and trans alkenes are them. possible when a molecule has two or more stereogenic centers that differ at some but not alll of the centers. they require multiple chiral centers.
2^n
how many stereoisomers can a molecule have with n chiral centers
meso compound
a molecule with an internal plane of symmetry
conformational isomer
most similar. same molecule only at different points in their rotation. show them with newmans projections
anti conformation
most favorable of staggared conformations
gauche conformation
methyl are 60 degrees apart. kinda stable
eclipsed conformation
highest energy no separation. or 120 separation.
ring strain
arise from angle strain, torsional strian and nonbonded strain
angle strain
when bond angles deviate from ideal values
torsional strain
results when cyclic molecules must assume conformations that have eclipsed interactions
nonbonded strain
results when nonadjacent atoms or groups compete for space. dominant source of energy in flagpole interactions of the boat conformation. thus it goes in various conformations like chair boat and twist.
ring flip
when boat flips
ionic bond
transfer of electrions from one atome to another
covalent bond
sharing of electron between atoms
quantum numbers
n, l, ml, ms
molecular orbital
when two atomic orbitals combine. obtained mathematically by adding or subtracting wave functions. if sings are the same, make bonding, if different, less stable antibonding.
sigma bond
when a molecular orbital is formed head to head or tail to tail. all single bonds are tehese.
pi bond
when two p orbitals line up in parallel and electron clouds overlap. it exsits over a single bond.
triple bond
a sigma bond and two pi bonds
hybridization
formed by mixing different types of orbitals
sp3
one s and three p orbitals
sp2
one s and two p 120 degree apart
sp
two p orbital form pi and third p orbital combine with s to make two sp hybrid. 180 degree apart
saturated hydrocarbon
no double bonds. it has the maximum number of hydrogens.
primary carbon
is bonded to only one other carbon atom
Combustion
reaction of alkane with oxygen to form carbon dioxide, water and heat.
C3H8 + 5O2 = 3CO2 + 4H2O + heat
combustion reaction occurs through a radical process
halogenation
in which one or morehydrogen atoms are replaced with a halogen atom. via free radical substitution
initiation propagation termination
steps of free radical substitution
pyrolysis
occur when a molecule is broken down by heat. used to reduce the avverage molecular weight of heavy oils. c-c- bonds are cleave dand make small chain alkyl radicals that recombine to form different alkanes
disproportionation
a radical transfers a hydrogen atom to another radical and makes an alkane and alkene
combustion, disproportionation, free-radical substitution, pyrolysis
alphabetical order of alkane rxn
nucleophile
nucleus lover. electron rich species that are attracked to charged atoms
electrophile
charged, need electrons
basicity
more likely it is to attract positively charged proton. nucleophilic strength decreses: RO->HO>RCO2>ROH>H2O
protic solvent
solvents with protons in solution, e.g. water or alcohol. large atoms tend to be better nucleophiles in here because they can shed the solvating protons around them and are more polarizable
aprotic solvent
not solvated
weak bases
what are the best leaving groups?
catalytic hydrogenation
reducing an alkene by adding molecular hydrogen to double bond with aid of metal catalyst. e.g. pt, pd, ni. takes place on surface of metal so it does syn addition
electrophilic addition
electrons of pi bond are reactive and easily attacked by molecules that want e pair e.g. electrophiles.
electrophilic addition of HX
e of double bond act as lewis base and react with hydrogen of hx. make carbocation intermediate. use markonikovs rule
markovnikov's rule
goal is to produce most stable carbocation
electrophilic addition of X2
fast process. double bond is nucleophile and attack x2. make cyclic halonium ion with either br or cl. and make dihalo trans
electrophilic addition of H2O
water can be added to alkenes under acidic conditions. make carbocation. ends with alcohol
electrophilic addition of free radicals
in presence of peroxide, oxygen or ultraviolet light. antimarkonikov because they want a stable free radical. therefore X ends up on least subsituted carbon
hydroboration
diborane add to double bond. boron acts as lewis acid and attaches to less hindered carbon. hydride transferred to adjacent carbon. antimarkonikov, alcohol produced
oxidation
if reagent has a bunch of oxygen
potassium permanganate
kmno4
cold potassium permanganate
alkenes oxidzed with kmno4, if made with cold, dilue, make OH on each side of double bond, diols or glycol in syn orientation
hot, acidic potassium permanganate
nonterminal alkenes are cleaved to form two molar equivalent of carvoxylic acid ..make keton
ozonolysis
O3
ozonolysis
cleaves double bond in half, it only oxidizes the carbon to an aldehyde under reducing conditions. if ozidizing make same product as KMNO4
oxidizing
ozonolysis under hot acidic kmO4, e.g. H2O2 condition
reducing
zn/h or CH3/s with ozonolysis
alcohol
what is produced when o3 with lialh4 or nabh4
peroxycarboxylic acid
alkene oxidized with this, strong oxidizing agent. CH3CO3H or mcpba and it makes epoxide or oxirane
mcpba
m-chloroperoxybenzoic acid
polymerization
creation of long, high molecular weight polymer composed of repeating subunit called monomers. occur through a radical mechanism.
alkyne
hydrocarbon with one or more carbon carbon triple bond
lindlar's catalyst
palladium or barium sulfate (BaSO4) with quinoline. occur on metal surface, make cis.