Group 6 Fischer carbene complexes:: chemical multitalents for multi-component reactions

The ability of heteroatom stabilized Fischer carbene complexes (FCCs) to participate in multicomponent reactions, which has allowed the construction of a large variety of highly functionalized structures through several patterns of reactivity, will be disclosed along the following lines. One of the main reasons for the high versatility and often unexpected behavior of FCCs relies on the possibility of incorporation of carbonyl ligands along the reaction pathway, depending on the reaction conditions. Thus, in this review there will be presented examples where up to five components react in a multicomponent sequence to create up to nine carbon-carbon bonds or to lead to the formation of up to seven stereogenic centers what points out the undisputable synthetic potential of FCCs. (C) 2004 Elsevier B.V. All rights reserved.