Abstract The intramolecular hydrosilylation of several 3-methyl-4-siloxy-2-butenoates afforded cis disubstituted lactones after desilylation. The diastereoinduction was sensitive to the bulk of the allylic substituent, but not to the groups on silicon. The origin of asymmetric induction is believed to be the A 1, 2 strain from the β-methyl group.
