CH 231 (Shaughnessy) 1 SN1 vs SN2 vs E1 vs E2
1° RX Reaction Type Requirements Small or straight‐chain, basic nucleophile ( , , , , etc.)
Only occurs with hindered strong bases , 2,2,6,6
Example ,
,
2° RX Reaction Type Requirements Strong non‐basic nucleophiles
,
,
:
Basic nucleophiles
& 1
,
Example S‐2‐iodopentane
R‐2‐cyanopentane
2‐bromopropane
2° allyli/benzylic (because of stabilization) Neutralor acidic conditions &/or protic solvents 1 perferred with better nucleophiles ( , , No good nucleophile present
:
(7%; 2) 3‐methyl‐1‐butyne + (93%; 2) propene + ethyne 3‐bromo‐1‐cyclohexene .
1,3‐cyclohexadiene ( 1 + 3‐hydroxyl‐1‐cyclohexene cyclohexanol ,
cyclohexene + water +
3° RX Reaction Type Requirements Doesn’t happen Basic conditions , & 1
Example (R,R)‐3‐bromo‐3,4,5‐trimethylhexane ,
,
:
Non‐basic or acidic conditions
Z‐2,3,4‐trimethyl‐3‐hexene 2‐bromo‐2‐methylpropane
No good nucleophile present
(80%; 1) methyl‐tertbutyl‐ether + (20%; 1) 2‐methyl‐propene 1‐methyl‐1‐hydroxylcyclohexane
(minor; 1) 1‐methyl‐1‐( )‐cyclohexane + (major; 1) 1‐methylcyclohexene (because is a poor nucleophile)
Tom Bertalan
[email protected]