10.1.7 Mitsunobu Reaction
The alkoxyphosphonium ion generated from diethyl azodicarboxyliate (DEAD), triphenyl phosphine and alcohol undergoes reaction with nucleophile (usually carboxylic acid) by SN2 character (Scheme 13-14). The reaction exploits, first, the reactivity of the azo compound as an electrophile in the formation of the first phosphonium ion and, second, the good leaving group property of the reduced azo compound.
Scheme 13
Mechanism
Scheme 14
Examples
10.1.8 Vilsmeier-Haack Reaction
This reaction allows formylation of the reaction of activated alkenes as well as arenes (Scheme 15).
Scheme 15
Mechanism
The formylating agent is generated in situ from DMF and POCl 3 (Scheme 16).
Scheme 16