Chapter 3
What is the lowest energy Newman projection configuration?
staggered
The highest is totally eclipsed.
Transition state, reaction intermediate
What types of molecule pair has different physical properties?
Diastereomers.
What is an alkyl halide? A vinyl halide?
alkyl: halogen bonded to sp3 carbon
vinyl: halogen bonded to sp2 carbon
What does E mean in E/Z nomenclature?
E means that the highest priority groups are opposite of each other.
Why is cyclopentane more stable than cyclobutane?
what is angle strain
According to the Hammond postulate what type of reaction resembles the products? The reactants?
Endothermic resembles product, exo reactants
How do you calculate the possible number of stereoisomers of a compound?
2^n with n being the number of chiral carbons.
What does the reaction rate of an SN2 reaction depend on? and What is the desired substitution degree for an SN2 reaction
Both the alkyl halide and nucleophile because it is concerted. The alkyl halide must be methyl or secondary.
Is cis or trans more polar?
Cis
Why is the chair confirmation favored?
It eliminates strain
What order is carbanion stability?
methyl>primary>secondary>tertiary
When determining R/S config, what needs to happen?
Lowest priority group must be in back.
Which reaction proceeds fastest in a polar protic solvent?
Sn1 because the Hydrogens stabilize the transition state.
What rule states that a Hydrogen will leave from the more substituted Carbon? What is the opposite rule?
Zaitsev. The opposite is Hoffman
What yields the most stable chair confirmation?
Subsituted groups in eq. positions.
Bromination vs. Chlorination. Which requires more energy and why?
Bromination requires more and is endothermic because it is much more selective than chlorine.
What happens to polarized light with a mixture of enantiomers?
Nothing, they point in opposite directions with the same magnitude.
What mechanism leads to a racemic mixture?
SN1
What type of molecule set up is required for an E2 reaction?
anti-coplanar
BONUS: What are the two dihydroxylation methods?
OsO4/H2O2 and KMMnO4, cold dilute
What is Hyperconjugation?
When a filled p orbital overlaps with an empty p orbital of a carbocation.(methyl groups can stabilize a carbocation better)
What is a meso compound?
Has a plane of symmetry and chiral carbons.
BONUS: What are the two ways in which you can convert a triple bond to a double bond?
H2, lindlars and Na,NH3
Bonus: What does peroxide do to a Halogenation reaction?
Makes the product anti markovnikov