Preparation, reactivities, and NMR spectra of pentafluorophenyltin derivatives

A variety of pentafluorophenyltin compounds were prepared and their chemica l properties were examined. These compounds effectively catalyzed Mukaiyama -aldol reaction of ketene silyl acetal in sharp contrast to the inertness o f normal alkyltin halides like Bu2SnCl2. The increased Lewis acidity of the pentafluorophenyltin halides was proved by Sn-119- and C-13-NMR spectra. O n the other hand, the pentafluorophenyl group reduced the reactivities of t in towards both nucleophiles and electrophiles. F-19-NMR spectroscopy was i nvoked to elucidate this anomaly. (C) 1999 Elsevier Science S.A. All rights reserved.