l-Phenylalanine potassium catalyzed asymmetric formal [3 + 3] annulation of 2-enoyl-pyridine N-oxides with acetone

Abstract

A highly enantioselective formal [3 + 3] annulation of 2-enoyl-pyridine N-oxides with acetone was developed. In this transformation, an amino-acid salt L-phenylalanine potassium proved to be a robust organocatalyst, and the corresponding annulation derivatives can be obtained with moderate to excellent yields (up to 99%) and good to excellent enantioselectivities (up to 94%).