The reactions of 1-(trimethylsiloxy)-3-methylcyclopent-1-ene, 1-(trime
thylsiloxy)-3-methylcyclohex-1-ene and 1-(trimethylsiloxy)-3,3-dimethy
lcyclohex-1-ene with various alkylating agents in the presence of silv
er trifluoroacetate produced the corresponding a,3-dialkylated and 2,3
,3-trialkylated cyclanones with high regiodifferentiation and stereose
lection.