Chemistry and applications of phosphonium and arsonium ylides(XXIX) - Studies on the hydrolysis of arsonium ylides containing perfluoroalkyl group and synthesis of 2-pyranone derivatives

In the presence of K2CO3, reaction of (2-naphthoyl)methyl arsonium bromide (1) with methyl 2-perfluoroalkynoates(2) in methylene chloride at room temperature afforded the adduct - methyl 4-(2-naphthoyl)-2-triphenylarsoranylidene-3-perfluoroalkyl-3-butenoates(3) as major product and 4-(2-naphthoyl)-4-triphenylarsoranylidene-3-perfluoroalkyl-2-butenoates (4) as minor product in high yield. Hydrolysis of compound 3 in V (CH3OH):V(H2O) = 9:1 methanolic solution at 80 degreesC in a sealed tube, 4-perfluoroalkyl-6-(2-naphthyl)-2-pyranones(5) was obtained in an excellent yield. The catalytic hydrolysis of compound 3 with silica gel and the mechanisms for the formation of the products will also be discussed.