THE REACTION OF 3-ACETYL COUMARIN WITH ALKYL PHOSPHITES AND PHOSPHONIUM YLIDES

Dialkyl phosphites reacted with 3-acetyl coumarin (1) at 100°C for about 5 h to give the phosphonates having structure 4. Methylation of compounds 4 with ethereal solution of diazomethane gave the respective methyl ethers 5. Treatment of 1 with trimethyl phosphite afforded a mixture of the phosphonates 5a and 4a whereas with triethyl phosphite gave a mixture of compounds 6 and 4b. The reaction of phosphonium ylides 8a-d with 1 in boiling toluene led to the formation of two isomers (E)-allylic (9) and (Z)-allylic (10). The structural assignments of all new compounds are based on IR and NMR (H, 13C) spectra.