Reductive cleavage of 2-methyleneoxetanes with lithium and 4,4′-di-tert-butylbiphenyl

3,3-Dimethyl-2-methylene-4-phenyloxetane (5) undergoes reductive cleavage with lithium and 4,4′-di-tert-butylbiphenyl (DTBB) to give an intermediate dianion, which reacts regioselectively with aldehydes and ketones to give aldol adducts in modest yields. Alternatively, the enolate can be trapped with TMSCl to give the corresponding silyl enol ether.