Issue in Honor of Prof. R. Rossi and Prof. E. Rúveda ARKIVOC 2003 (x) 443-467 The influence of protecting groups on the diastereoselectivity of catalytic heterogeneous hydrogenation of Baylis-Hillman adducts Fernando Coelho,* a Wanda P. Almeida,* b Cristiano R. Mateus, a Leonardo D. Furtado, a and José Carlos F. Gouveia a a DQO/IQ – UNICAMP- PO Box 6154 – 13084-917 – Campinas, S – Brazil b Curso de Pós-Graduação em Biologia Celular e Estrutural – IB/UNICAMP – PO Box 6109 – 13084-971 – Campinas, SP - Brazil . E-mail: coelho@iqm.unicamp.br; wandaalmeida@terra.com.br This article is dedicated to Prof. Edmundo Ruveda on occasion of his 70 th anniversary (received 30 Aug 03; accepted 15 Oct 03; published on the web 22 Oct 03) Abstract In this communication we describe our recent results from a study on catalytic heterogeneous hydrogenation reactions of Baylis-Hillman adducts. Depending on the protecting groups used on the secondary hydroxyl group of these adducts, it is possible to obtain a high degree of diastereoselection. For silylated Baylis-Hillman adducts a high syn diastereoselectivity has been obtained. However, when secondary Baylis-Hillman hydroxyl groups were unprotected or protected as acetate a moderate anti selectivity was attained. The adducts protected as methyl ether gave poor syn diastereoselectivity. Keywords: Baylis-Hillman, diastereoselectivity, heterogeneous hydrogenation Introduction The Baylis-Hillman reaction is a simple and straightforward alternative to generate a new C-C σ bond. In the last few years this reaction has attracted the attention of many organic chemists, mainly due to the great synthetic potentiality of the α-methylene-β-hydroxy compounds (Figure 1) provided by it, associated with its operational simplicity (no special experimental conditions such as low temperature, anhydrous solvent or inert atmosphere are required). This reaction may be broadly defined as a coupling between the α-position of activated alkenes and an electron- deficient sp 2 carbon atom, for instance an aldehyde carbonyl group. The reaction is usually catalyzed by DABCO (1,4-diazabicyclo [2.2.2.] octane) or a phosphine. 1 ISSN 1551-7012 Page 443 © ARKAT USA, Inc