The influence of protecting groups on the diastereoselectivity of catalytic heterogeneous hydrogenation of Baylis-Hillman adducts

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.