Bases and nucleophiles for Sn and E

Orgo 1 chapter 6

H2O

weak nuc and weak b

ROH

weak nuc and weak b

H2S

weak nuc and weak b

CN-

strong nuc weak b

N3-

strong nuc weak b

RCOO-

strong nuc weak b

X-

strong nuc weak b

HS-

strong nuc weak b

RS-

strong nuc weak b

HO-

strong nuc strong b

NH2-

strong nuc strong b

RO-

strong nuc strong b

LDA

weak nuc strong b

*full name: LiN(CH(CH3)2)2

KOtBu

weak nuc strong b

*full name: KOC(CH3)3

bases attack __ in order to do __

hydrogens, elimination

nucleophiles attack __ in order to do __

electron-deficient atoms, substitution

Characteristics of a good “leaving group” (all SN and E)

if CA is a strong acid (aka is a weak base) and has a low pKa value

Characteristics of a bad “leaving group” (all SN and E)

if CA is a weak acid (aka is a strong base) and has a high pKa value

Base definition

donates electrons to abstract a proton (H+)

Nucleophile definition

donates electrons to attack electrophilic atom (any other than hydrogen)

*forms new covalent bond in the process

All __ are __, but not all __ are __ (fill in base or nucleophile)

bases, nucleophiles

nucleophiles, bases