Catalytic Enantioselective Aza Diels-Alder Reactions of Imino Dienophiles

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.