Asymmetric Organocatalytic Synthesis of Chiral Polycyclic 1,4-Dihydropyridines and Axially Chiral 4-Arylpyridines Using 2,3-Dioxopyrrolidines and 1,3-Diketones

Abstract

An asymmetric Michael/hemiketalization/amination reaction of 1,3-diketones with 2,3-dioxopyrrolidines catalysed by a quinine-derived urea catalyst has been developed, which furnished a series of chiral polycyclic 1,4-dihydropyridines in satisfactory yields and enantioselectivities (35–94 % yield for two steps and up to 99 % ee). Moreover, the subsequent oxidative aromatization of chiral 1,4-dihydropyridines delivered chiral atropisomeric 4-arylpyridines in 69–94 % yield and up to 95 % ee.