Synthesis of Axially Chiral Biaryls via Enantioselective Ullmann Coupling ofortho‐Chlorinated Aryl Aldehydes Enabled by a Chiral 2,2′‐Bipyridine Ligand

Abstract

AbstractThe first nickel‐catalyzed highly enantioselective reductive Ullmann coupling ofortho‐chlorinated aryl aldehyde was achieved under mild reaction conditions with a chiral 2,2′‐bipyridine ligand (+)‐DTB‐SBpy, thus providing axially chiral biphenyl or binaphthyl dials with up to 99 % yield and 99.5:0.5 er. The versatility of the products as common synthetic intermediates for diverse axially chiral ligands, catalysts, and functional molecules was demonstrated by short‐step transformations. This protocol also allowed the concise and highly enantioselective formal total synthesis of biologically active natural products (+)‐kotanin, (−)‐isoschizandrin and (+)‐gossypol.