pKa values, nucleophilic substitution and elimination, and common solvents

H-Cl

-7

Anhydride

-6.9

CH3COO-H

4.8

H3CC=OCH2C=OCH3

9

HO-H

15.7

CH3CH2O-H

16

aldehyde

17

Ketone

19.2

ester

22-25

HC=CH

25

Nitrile

25

Amide

30

H-H

35

H2-N-H

38

CH2=CH2

44

CH3-H

50

Alkyl Substrate for SN1

Formation of a relatively stable carbocation 3°>2°

Alkyl Substrate for SN2

Unhindered substrate Me>1°>2°

Alkyl Substrate for E1

3° (2°)

Alkyl Substrate for E2

3°>2°>1°

Nucleophile for SN1

Weak Lewis Base, neutral molecule, solvolysis

Nucleophile for SN2

Strong Lewis base (anion), rate increased by high [ ]

Nucleophile for E1

Base, not Nucleophile; weaker bases favor E1 (H2O, ROH)

Nucleophile for E2

Strong base, bulky (KO’Bu, DBU)

Solvent for SN1

Polar, protic (H2O, alcohols, acids)

Solvent for SN2

Polar, aprotic (DMSO, DMF, ACN)

Solvent for E1

Polar, protic

Solvent for E2

Polar, aprotic

Benzene

Non-polar

Toluene

Non-polar

n-Hexane

Non-polar

Dioxane (6-membered ring w/ meta oxygens)

Polar (weak)

Tetrahydrofuran (THF) (cyclopentane with an O in the ring)

Polar (weak)

Diethyl ether

Polar (weak)

Chloroform (CHCl3)

Polar (moderate)

Dichloromethane (methylene chloride)

Polar (moderate)

Methanol (CH3OH)

Polar (strong)-protic

Ethanol

Polar (strong)-protic

Isopropanol

Polar (strong)-protic

Acetonitrile (H3C-C=N)

Polar (strong)-non-protic

Acetone (H3C-C=O -CH3)

Polar (strong)-non-protic

Dimethylsulfoxide (DMSO)

Polar (strong)-non-protic

N, N-Dimethylformamide (DMF)

Polar (strong)-non-protic

Ethyl acetate (EtOAc)

Polar (strong)-non-protic