Asymmetric cooperative catalysis of strong Bronsted acid-promoted reactions using chiral ureas.

ABSTRACT: Cationic organic intermediates participate in a wide variety of useful synthetic transformations, but their high reactivity can render selectivity in competing pathways difficult to control. Here, we describe a strategy for inducing enantioselectivity in reactions of protio-iminium ions, wherein a chiral catalyst interacts with the highly reactive intermediate through a network of noncovalent interactions. This interaction leads to an attenuation of the reactivity of the iminium ion and allows high enantioselectivity in cycloadditions with electron-rich alkenes (the Povarov reaction). A detailed experimental and computational analysis of this catalyst system has revealed the precise nature of the catalyst-substrate interactions and the likely basis for enantioinduction.

SUBMITTER: Xu H 

PROVIDER: S-EPMC2993568 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature