CHIRAL HOMOENOLATE EQUIVALENTS - 6 - ASYMMETRIC-SYNTHESIS OF BETA-METHYLATED ALIPHATIC-KETONES VIA LITHIATED 3-[(S)-2-(METHOXYMETHYL)PYRROLIDINO]HEX-3-ENE

3-Substituted aliphatic ketones 10 have been obtained in excellent opt ical yields by alkylation of the aminoallyllithium compound endo-8, a homoenolate equivalent of hexane-3-one, using prolinol ether (SMP) as the chiral auxiliary. The intermediate endo-8 was generated by tin-lit hium exchange of the 3-stannylated enamine 7a with butyllithium. An im proved hydrolysis procedure for the resulting enamines is described. S ome mechanistic implications with respect to the formation as well as the alkylation of endo-8 are discussed.