Control of Diastereoselectivity in Tandem Asymmetric Reactions Generating Nonadjacent Stereocenters with Bifunctional Catalysis by Cinchona Alkaloids
摘要:
We report the manipulation of hydrogen-bonding-based cooperative catalysis to control the diastereoselectivity for a tandem asymmetric reaction creating two nonadjacent stereocenters. This ability to control both the enantioselectivity and diastereoselectivity allows, for the first time, the direct and stereoselective construction of 1,3-tertiary-quaternary stereocenters in any of the possible four configurations from the same prochiral precursors with catalytic control. The synthetic consequence of such catalyst-controlled construction of nonadjacent stereocenters is illustrated by the asymmetric synthesis of manzacidin C by using the same reaction sequence that was previously applied to the total synthesis of manzacidin A.
Control of Diastereoselectivity in Tandem Asymmetric Reactions Generating Nonadjacent Stereocenters with Bifunctional Catalysis by Cinchona Alkaloids
摘要:
We report the manipulation of hydrogen-bonding-based cooperative catalysis to control the diastereoselectivity for a tandem asymmetric reaction creating two nonadjacent stereocenters. This ability to control both the enantioselectivity and diastereoselectivity allows, for the first time, the direct and stereoselective construction of 1,3-tertiary-quaternary stereocenters in any of the possible four configurations from the same prochiral precursors with catalytic control. The synthetic consequence of such catalyst-controlled construction of nonadjacent stereocenters is illustrated by the asymmetric synthesis of manzacidin C by using the same reaction sequence that was previously applied to the total synthesis of manzacidin A.