Benzoyl peroxide reaction with enamines

As depicted in Scheme 7, the synthesis of the mosquito oviposition pheromone (-)-6-acetoxy-5-hexadecanolide (28) via an intermolecular aldol reaction represents a powerful demonstration of the high potential of asymmetric enamine catalysis (45, 46). It is noteworthy that a methodologically different successful organocatalytic approach towards 28, based on an asymmetric a-oxygenation, was reported recently (727). Reaction of aldehyde 136 with dibenzoyl peroxide (BzOOBz) and hydroqui-none (HQ) (722) in the presence of the TMS-protected prolinol catalyst (S)-138 followed by a direct allyation gave the benzoyl-protected 139 in moderate yield and good selectivity. Intermediate 139 could then be further transformed to give (—)-(57 ,65)-6-acetoxy-5-hexadecanolide (28) (Scheme 33). 

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