CHIRAL SULFOXIDE CONTROLLED ASYMMETRIC ADDITIONS TO C-N DOUBLE-BOND -AN EFFICIENT APPROACH TO STEREOCHEMICALLY DEFINED ALPHA-FLUOROALKYL AMINO-COMPOUNDS

This paper presents a full account of studies into the asymmetric addi tion reactions between alpha-lithium derivatives of enantiomerically p ure methyl and benzyl p-tolyl sulfoxides and the N-(p-methoxyphenyl)al dimines, bearing trifluoromethyl, pentafluoroethyl and omega-hydrotetr afluoroethyl groups, to afford the corresponding alpha-fluoroalkyl bet a-sulfinylamines, synthetically versatile precursors of a series of en antiomerically pure biomedicinally important alpha-fluoroalkylalkylami nes and alpha-fluoroalkyl-beta-hydroxyalkylamines. The addition reacti ons were found to proceed under mild conditions allowing for convenien t preparation of the corresponding alpha-fluoroalkyl beta-sulfinylamin es in excellent yields and good enantiomeric purity. The stereochemica l outcomes of these reactions were shown to be subject to kinetic cont rol, that is in sharp contrast to the corresponding reactions of fluor ine-free imines. The absolute configurations of the addition products suggest that the fluoroalkyl group on starting imines plays a role of enantiodirecting, sterically larger substituent causing realization of an unusual for this type of reactions transition states. (C) 1998 Els evier Science Ltd. All rights reserved.