The epoxidation of allylic alkenes in the 6-tert-bulyl (or 6-trimethylsilyl or 6-trimethylgermyl) 3,3-dimethylcyclohexenes is examined; it has been found that the stereochemistry of these reactions is governed mostly by steric factors. The results obtained by the reduction ofcisandtransepoxides by lithium aluminium hydride are also reported, the regiochemistry and the stereochemistry of the reactions of reduction are governed by steric factors as well as by the electronic effects of the trimethylsilyl group.