Elimination reactions Flashcards
1
Q
E1 involves…
A
Formation of C+ intermediate
Favors SM w/ C bond to LG being3>2>1
Allylic or benzylic C favored
Acidic or peptic conditions
2
Q
E2 involves…
A
No C+ intermediate No preference for substitution of Csp3 bonded to LG 3=2=1 Favored under basic conditions Run under thermo conditions
3
Q
Kinetic v Theromdynamic
A
Kinetic products form the fastest while thermodynamic products are the most stable
4
Q
Elimination of Alcohols
A
-OH is poor LG and must be “activated” before rxn progresses
Forms an Oxonium ion b/c H2O is good LG
5
Q
E1 acids
A
Use strong acids w/ conj bases that are weak nucleophiles
H2SO4
H3PO4
CH3CO2H
*NOT HCl or HBr because conj bases are halides (good Nu)
6
Q
E2 Reagent
A
POCl3 is used to activate OH in E2 Bases are used in addition to POCl3 Et3N: triethyl amine Pyr: pyridine (benzene ring w/ N inside) Rxn does not occur if H is not trans to LG (Nu will not attack)
