Synthesis and odor characteristics of isomeric 3,3,7-trimethyl-4-octen-1-ols and their 3-sila analogues

The isomeric (E) and (Z) 3,3,7-trimethyl-4-octen-l-ols and their 3-sila analogues were synthesized. The (Z) 3,3,7-trimethyl-4-octen-l-ol was obtained by the isomerization of E alcohol via its epoxide deoxygenation according to the Vedejs method. Both sila analogues were synthesized from 4-methyl-l-pentyne. The carbon chain was elongated by alkyne silylation with dimethylvinylchlorosilane (synthesis of Z isomer) or by hydrosilylation with dimethylchlorosilane followed by Reformatsky reaction with ethyl bromoacetate (synthesis of isomer E). Odors of alcohols obtained and their acetates have been also evaluated. The odors of carbon compounds are more intense and more fresh than their silicon analogues.