Enantioselective installation of quaternary centers in cyclic oxonitriles

Abstract

Quaternary centers are rapidly and selectively installed in a series of seven-membered and bridged cyclic oxonitriles through conjugate addition of an alkoxide to chloroalkenenitriles, followed by a Claisen rearrangement. Using this strategy, the stereogenic information of the carbinol in secondary allylic alcohols is transferred to the newly generated quaternary center. Experimentally, the sequence rapidly gives alkyl cyanocycloheptanones and bicycloalkanonecarbonitriles in good yield and with high selectivity, in a single synthetic operation.