Challenge toward Structural Complexity Using Asymmetric Catalysis:  Target-Oriented Development of Catalytic Enantioselective Diels−Alder Reaction

Abstract

A new method for the catalytic enantioselective Diels−Alder reaction using polysubstituted silyl enol ethers as dienes is described. High enantioselectivity (up to 92% ee) was produced using a catalyst generated from FeBr3 and AgSbF6 in a 1:2 ratio and aryl-pybox (aryl = Ph or p-ethoxyphenyl). This reaction should facilitate the enantioselective synthesis of polycyclic acylphloroglucinols such as hyperforin or garsubellin A, which are currently of interest from synthetic and medicinal points of view