Orgo Ch. 3

formula for alkane
angle strain (Baeyer strain)
the strain associated with compressing bond angles to smaller (or larger) angles
anti conformation
a conformation with a 180 degree dihedral angle between the largest groups. usually the lowest-energy conformation.
bridged bicyclic compound
a compound containing two rings joined at nonadjacent carbons.
bridgehead carbons
the carbons bridging two separate rings.
ring flip
switching from one chair conformation to the next, with all the axial and equatorial positions reversed. the boat conformation is an intermediate for this interconversion.
structures that are related by rotations about single bonds. in most cases, conformations interconvert at room temperature, and so they are not true isomers
conformations of cyclohexanes:
1. chair-most stable
2. boat: less stable
3. twist boat- more stable version of twist boat (twist reduces torsional strain and steric strain)
4. half-chair
flagpole hydrogens
two hydrogens in the boat conformation point upward like flagpoles.
1,3 diaxial interaction
the strong steric strain between two axial groups on cyclohexane carbons with one carbon between them.
degree of alkyl substitution
primary, secondary, tertiary, or quaternary
dihedral angle
the angle between two specified groups in a newman projection.
gauche conformation
a conformation with a 60 degree dihedral angle between the largest groups
the reaction of alkanes with halogens, in the presence of heat or light, to give products with halogen atoms substituted for hydrogen atoms.
heat of combustion
the heat given off when a mole of a compound is burned in a bomb calorimeter.
two compounds that differ only by one or more -CH2 groups (eg ethane vs. propane)
a thin, volatile hydrocarbon with a boiling range between that of diesel fuel and that of gasoline.
methane hydrate
an icelike substance consisting of individual methane molecules trapped inside cages of water molecules
methine group
carbon bonded to two other things and one hydrogen
methylene group
ring strain
angle strain (baeyer strain): bond angle compression or expansion
torsional strain: the strain associated with eclipsing of bonds in the ring.
skew conformation
any conformation that is not precisely staggered or eclipsed.
spirocyclic compound
bicyclic compounds in which the two rings share only one carbon atom.
torsional energy
the energy required to twist a bond into a specific conformation.