Two Distinct Ag(I)- and Au(I)-Catalyzed Olefinations between α-Diazo Esters and N-Boc-Derived Imines.

Metal-catalyzed reactions between α-diazo esters and imines were well-known to yield aziridine derivatives exclusively. This work reports two new olefination reactions between N-Boc-derived (Boc = tert-Butyloxycarbonyl) imines and α-diazo esters with Ag(I) and Au(I) catalysts, respectively. Our mechanistic studies reveal that these new olefinations involve an initial attack of diazo esters on metal/imine complexes to form Mannich-addition intermediates, which subsequently afford α-aryl-β-aminoacrylates via a Roskamp reaction, or to form β-aryl-β-aminoacrylates via the formation of silver carbenes.