Facile Synthesis of Pyrrolyl 4-Quinolinone Alkaloid Quinolactacide by 9-AJ-Catalyzed Tandem Acyl Transfer-Cyclization of -Alkynoylaniline Derivatives.

The synthesis of pyrrolyl 4-quinolinone alkaloid, quinolactacide, and its analogues was successfully achieved using 9-azajulolidine (9-AJ)-catalyzed tandem acyl transfer-regioselective cyclization of ,-diacyl--alkynoylaniline derivatives. In addition, this organocatalytic reaction was successfully utilized for the synthesis of a variety of 3-acyl-4-quinolinones in moderate-to-good yields. Mechanistic studies, including a time course nuclear magnetic resonance (NMR) experiment, indicated that the 1,4-addition of 9-AJ to an ynone system can be considered to be the rate-determining step in this quinolinone synthesis.