Pheromone synthesis. 4. A synthesis of (.+-.)-methyl n-tetradeca-trans-2,4,5-trienoate, an allenic ester produced by the male dried bean beetle Acanthoscelides obtectus (Say)
Pheromone synthesis. 4. A synthesis of (.+-.)-methyl n-tetradeca-trans-2,4,5-trienoate, an allenic ester produced by the male dried bean beetle Acanthoscelides obtectus (Say)
using n-Bu4NBr afforded 2-cyano-2-siloxyvinylallenes via a tandem process that involves a nucleophilic attack of a cyanide ion and a Brookrearrangement induced conjugate vinylic 1,4-elimination. Use of a chiral cyanide ion source, derived from KCN and quaternary ammonium bromide derived from cinchona alkaloids, provided nonracemic allene derivatives. Based on this result and the reaction using a chiral