OCHEM DECISION TREE

1 in general

SN2 or E2

2 in general

E2 / SN2 + something else (basically all)

3 in general

SN1 → E2 gradient

1 nucleophile

SN2

1 Trim Base

SN2

1 bulky base

E2

2 good nucleophile

SN2 or SN1

2 weak nucleophile

SN2 and E1

strong base

E2

3 good nucleophile

SN1

3 weak nucleophile

SN1 and E2

3 strong base

E2

higher temp favors

elimination

bulky base double bond

side

trim base double bond

middle

SN1

2 steps, leaving group leaves and forms carbocation, nucleophile attacks cation to form product, plain lines

SN2

1 step with 2 arrows, nucleophile back attacks leaving group which leaves at same time

E1

2 step, leaving group leaves, attacks poorer C resulting in double bond

E2 reaction

one step, attack least sub H create double bond