Chemoselective reduction of prostaglandin intermediates by liquid-phase hydrogen transfer on Pt±Sn/MCM-41 catalysts S. Coman a, * , F. Cocu b , V.I. Parvulescu a , D. De Vos c , P.A. Jacobs c a Department of Chemical Technology and Catalysis, Faculty of Chemistry, University of Bucharest, B-dul Regina Elisabeta 4-12, Bucharest 70346, Romania b Chemical and Pharmaceutical Research Institute, Vitan Avenue 112, Bucharest 74312, Romania c Departement Interfasechemie, Katholieke Universiteit Leuven, Kardinaal Mercierlaan 92, Heverlee B-3001, Belgium Received 14 February 2000; accepted 15 April 2000 Abstract Pt±Sn/MCM-41 reduction catalysts were prepared by a two-step impregnation procedure. The eect of the Sn content was evaluated in the liquid-phase hydrogen transfer reduction of an enone prostaglandin intermediate. Results indicate that up to a Sn/Pt atomic ratio of 3.3 increasing amounts of Sn favor the formation of the allylic alcohol. The reaction also displays moderate diastereoselectivity. On the other hand, the Pt/MCM-41 catalyst produces the saturated ketone as the main reaction product. Ó 2001 Elsevier Science B.V. All rights reserved. Keywords: Transfer hydrogenation; Formic acid±triethylamine mixture; Bimetallic supported catalysts; Prostaglandin intermediate; Diastereoselectivity 1. Introduction The selective reduction of a,b-unsaturated al- dehydes and ketones to the corresponding alcohols has found major applications in the synthesis of various ®ne chemicals and pharmaceuticals. Sev- eral attempts have been made to develop a suitable catalytic system for this kind of reaction [1±8]. Supported bimetallic catalysts, such as Pt,Rh,Ru)± Sn,Fe,Mn) on SiO 2 or Al 2 O 3 have been frequently investigated for reduction of unsaturated carbonyl compounds. Among these, Pt±Sn emerges as the most interesting system. However, such Pt±Sn catalysts have not yet been applied to the synthesis of prostaglandins. Moreover, this type of catalyst is seldomly used with alcohols or formic acid±tri- ethylamine as reductants. The diverse clinical applications of prostaglan- dins re¯ect their wide-ranging physiological and pharmaceutical properties [9]. Synthetic analogues have been developed with the aim of obtaining compounds that are more stable, have a longer duration of action and a more speci®c eect. For instance, cloprostenol is a synthetic analogue of prostaglandin F 2a ; it is used as a luteolitic agent in veterinary medicine. In this paper we report on the eect of the Sn content on the Pt±Sn/MCM-41 catalyzed transfer hydrogenation of a prostaglandin intermediate, with a formic acid±triethylamine mixture HCOOH/ NEt 3 ) as hydrogen donor. The conversion and Microporous and Mesoporous Materials 44±45 2001) 477±482 www.elsevier.nl/locate/micromeso * Corresponding author. 1387-1811/01/$ - see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII:S1387-181101)00223-2