In the presence of K2CO3, reaction of (2-naphthoyl)methyltriphenylphosphoni
um bromide (1) with methyl 2-perfluoroalkynoates (2) in CH2Cl2 at room temp
erature gave methyl 4-(2- naphthoyl)-2-triphenylphosphoranylidene-3-perfluo
roalkyl-3-butenoates (3) as major products and methyl 4-(2-naphthoyl)-4-tri
phenylphosphoranylidene-3-perfluoroalkyl-2-butenoates r4) as minor products
in excellent yields. 4-Perfluoroalkyl-6-(2-naphthyl)-2-pyranones (5) were
obtained in high yield by hydrolysis of the methylene phosphoranes (3) in h
ot aqueous methanol in a sealed tube. The structures of compounds 3, 4, and
5 were confirmed by IR, MS, H-1, F-19 and C-13 NMR, and microanalyses. Rea
ction mechanisms are proposed to account for the formation of products 3, 4
, and 5. (C) 2001 Elsevier Science B.V. All rights reserved.