Chapter 8 Flashcards
(31 cards)
Requirements of an elimination reaction
a strong base
when are mixtures possible in elimination reactions?
when multiple beta-hydrogens are present
Zaitsev’s Rule
major product of beta-elimination will the most stable alkene
how many steps in E1
2 steps, a fast step and a slow step
Amount of steps in E2
1, much like SN2
what stereochemistry is favorable in E2 rxn
anti and coplanar (H and X in same plane)
SN1 vs E1
- difficult to predict, need experiments to verify
- results in mixtures of each
SN2 vs E2
- Good nucleophile increases ratio of SN2
- High basicity of Nucleophile increases ratio of E2
naming an Alkene
Number the carbon chain and mark position where dbl bond starts
Alkenyl group
same as alkyl groups for alkenes
Possibilities of Cyclic acids
Double bonds may be in the ring or out of the ring
Endocyclic Double bonds
Dbl bonds inside the ring
Exocyclic Dbl Bonds
out of the ring
when is methylene used in naming
when Dbl bond is exocyclic
C2 to C4 alkenes are
gases at STP
Highly substituted alkenes are
more stable
Why are highly subbed alkenes more stable?
SP2 hybrid atoms attract electrons. since R groups are e- donators, then this donation stabilizes the SP2 C
Cis/trans more stable?
trans isomers are more stable
why are trans isomers more stable
the two substituents cause strain in the cis molecule
Dehydrogenation
rxn that loses hydrogen gas (H2)
Dehydration of alcohols causes
loss of H2O from an alcohol
Which type of carbon is easiest to hydrate?
tertiary
Zaitsev rule- applied to dehydration
elimination reactions of alcohols yield the most highly substituted alkene as the major product
rates of reactivity for E1 and E2
- Primary are the slowest
- tertiary are the fastest
