Asian J Org Chem 2014 Apr;3(4):453-457
Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Dr. East, Los Angeles, California 90095-1569 (USA).
Phosphinocatalysis provides a new approach toward 3-substituted-4-quinolones. A simple procedure, which uses PhP as an inexpensive catalyst and -phenyl 2-(-tosylamido)benzothioates and activated alkynes as starting materials, provides direct access to several 3-aroyl-4-quinolones and methyl 4-quinolone-3-carboxylate esters. The reaction presumably occurs through general base catalysis, with the initial addition of PhP to the activated alkyne generating the phosphonium enoate zwitterion, which acts as the strong base that initiates the reaction. Read More