Application of Homophthalic Anhydrides as 2C Building Blocks in Catalytic Asymmetric Cyclizations of ortho‐Quinone Methides: Diastereo‐ and Enantioselective Construction of Dihydrocoumarin Frameworks

Abstract

AbstractA catalytic asymmetric [4+2] cyclization of ortho‐quinone methides with homophthalic anhydrides in the presence of chiral squaramide‐tertiary amine has been established. This method provides dihydrocoumarin frameworks in excellent diastereoselectivities (all >95:5 dr) and high enantioselectivities (81%–98% ee). This reaction represents the first application of homophthalic anhydrides as 2C building blocks in catalytic asymmetric cyclizations. In addition, this approach not only provides a useful method for constructing enantioenriched dihydrocoumarin frameworks but also advances the chemistry of catalytic asymmetric cyclizations of ortho‐quinone methides.magnified image