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
Ethers, esters and amides of dodeca-2,4-dien 1-ols or 1-oic acids which have a methyl or ethyl side chain at the 11-position which are useful in killing and preventing proliferation of insects, by upsetting their hormone balance and a process for preparing these ethers, esters and amides including intermediates in this process.