Chemical & Pharmaceutical Bulletin 2000-07-01

alpha,alpha-gem-Difluorination of alpha-(alkylthio)acetophenone derivatives with N-fluoropyridinium salts.

S Takeda, Y Kaneko, H Eto, M Tokizawa, S Sato, K Yoshida, S Namiki, M Ogawa

Index: Chem. Pharm. Bull. 48(7) , 1097-100, (2000)

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Abstract

The alpha,alpha-gem-difluorination of 2',4'-difluoro-alpha-(methylthio)acetophenone (1a) with N-fluoropyridinium salts gave 2',4',alpha,alpha-tetrafluoro-alpha-(methylthio)acetophenone (3a). This reaction was accelerated by the addition of zinc chloride, zinc bromide or anhydrous iron(III) chloride, and higher yields than the reaction without additives were obtained. The gem-difluorination reaction using FP-T300 in the presence of zinc bromide was applicable to other alpha-(alkylthio)acetophenone derivatives (1).