Organocatalytic Asymmetric Tamura Cycloaddition with α- Branched Nitroolefins: Synthesis of Functionalized 1-Tetralones.

A new catalytic asymmetric Tamura cycloaddition with nitroolefins was developed. This demonstration of the reaction of α-branched nitroolefins with homophthalic anhydrides delivers highly functionalized 1-tetralone compounds. With bifunctional squaramide catalyst, the desired tetralone products are obtained with high enantioselectivity and good diastereoselectivity.