Catalytic enantioselective aza Diels-Alder reactions of imino dienophiles

Abstract

1 mol% of catalyst is sufficient: The hetero Diels-Alder reaction of α- imino esters 1 with activated conjugated dienes 2 (R = H, Me) needs only 1 mol% of a 2,2'-bis(diarylphosphanyl)-1,1'-binaphthyl (BINAP) copper(I) complex as the catalyst to generate the adducts 3 in good yields and with enantioselectivities up to 96%. The reaction can also be carried out on gram scale! Tos = H3CC6H4SO2; TMS = Me3Si.