Exam 3: Chapter 9 Reactions - Substitution/Elimination

Strong + bulky base →

E2

Strong base + 1 prime substrate →

SN2

Strong base + 2 prime substrate →

E2

Strong base + 3 prime substrate →

E2

Weak base + 1 prime substrate →

SN2

Weak base + 2 prime substrate + good nucleophile →

SN2

Weak base + 2 prime substrate + poor nucleophile →

SN1

Weak base + 3 prime substrate →

SN1

Poor nucleophiles =

neutral oxygen (ex: H2O, ROH, RCO2H)

Good nucleophiles =

I-, Br-, HS-, HO-, RO-, CN-, N3-, H2N-, R2N-

Strong bases =

un-stabilized C-, N-, O- anions (ex: RO-, OH-, R2N-, C-)

Strong bases pKa =

pKa > 12

Weak bases =

stabilized C-, N-, O- (ex: RCO2-, CN-, N3-, HS- RS-)

Weak base pKa =

pKa < 12

What reaction will all methyl substrates (ex: CH2Br) be?

SN2

E2 reactions follow what rule and what is exception?

Zaitsev’s rule except when it is a bulky base.

Elimination favors __ bases.

strong

Substitution favors __ bases.

weak

What is nucleophilic substitution?

any reaction where a NU- replaces a leaving group (Lv)