A [4+2] cycloaddition of push-pull styrenes to 1,2-naphthoquinone 1-methides: a synthesis of 2-aryl-2,3-dihydro-1H-benzo[f]chromenes

Abstract

A regioselective and trans-diastereoselective method for the preparation of 2-aryl-2,3-dihydro-1H-benzo[f]chromenes based on 2-naphthol Mannich bases as precursors of 1,2-naphthoquinone 1-methides and highly polarized β-(N,N-dimethylamino)styrene was developed. The resulting cycloadducts were transformed into cyclic acetals and hemiacetals as well as introduced into the Cope reaction leading to 2-aryl-1H-benzo[f]chromenes.