Difluoromethyl phenyl selenoxide (2) has been prepared and allowed to react with acetic anhydride in the presence of cyclic ethers and sulfides. Difluorophenylselenomethylation occurred smoothly on reacting 2 with Ac2O in refluxing dichloromethane to give omega-[difluoro(phenylseleno)methoxy]alkyl acetates 4 in 34-87% yields. A sequential reaction of Pummerer type rearrangement, difluorocarbene formation, electrophilic addition of the carbene to oxygen of ethers leading to oxonium ylide, and trapping with phenylselenenyl acetate is proposed.
Uneyama Kenji, Maeda Kazuhiro, Tokunaga Yukio, Itano Nobuaki, J. Org. Chem., 60 (1995) N 2, S 370-375