Ir[(COD)(PPh3)(2)]OTf activated by H-2 molecule catalyzes Michael-type coupling of alpha,beta-enones with enoxysilanes to give 1,5-dicarbonyl compounds after the subsequent protodesilylation. An identical catalyst system makes it possible to attain a continuous Michael and aldol modification toward alpha,beta-enones in a one-pot operation. (C) 2000 Elsevier Science Ltd. All rights reserved.