Gold-Catalyzed Annulation Between 1-[2-(Dimethoxymethyl)phenyl]prop-2-yn-1-yl Acetates and α-Diazo Esters or Anilines to Form Substituted Naphthoates and Indeno[1,2-b]quinoline, Respectively

This work describes gold-catalyzed annulations of 1-(2-(dimethoxymethyl)phenyl)-1-prop-2-yn-1-yl acetate substrates with alpha-diazo esters and anilines, respectively yielding substituted naphthoates and indeno[1,2-b]quinoline derivatives. Our mechanistic analysis indicates 1-methoxy-2-carbonyl-1H-indenes as their common intermediates. In the formation of naphthoates, alpha-diazo ester attacks at gold-bound intermediate via an SN2 pathway to enable a allylic methoxy substitution. For indeno[1,2-b]quinoline derivatives, there are two main reactions, including (i) a reversible formation between intermediate and a double amine addition product and (ii) an arylation reaction of intermediate. Species N-(phenyl((2E)-1-(phenylimino)-1,3-dihydro-2H-inden-2-ylidene)methyl)aniline was converted to indeno[1,2-b]quinoline in the presence of gold catalyst.