Two or More CH Bond(s) Formed by Addition to CC Multiple Bonds

Abstract

This chapter describes the formation of at least two CH bonds by addition to multiple bonds. The reduction of alkenes is first discussed. In a general overview, heterogeneous and homogeneous hydrogenations are first described. Recent advances concerning the development of new ligands (chiral ligands, monodentate phosphorus ligands, and carbenes), new reaction media (biphasic systems, supercritical fluids, ionic liquids, fluorous solvents), or new catalytic systems (supported aqueous phase catalysts, grafted metals on various supports, nanoparticles, nanoclusters, bimetallic catalysts) are summarized. Stoichiometric methods based on diimide, metallic hydrides, dissolving metals, or ionic hydrogenations are presented, as well as the recent developments of metal-catalyzed conjugate reductions. Enzymatic and biomimetic reductions close this short presentation. Recent developments in the reduction of alkyl, alkenyl, aryl, alkynyl, heteroaryl alkenes, and remotely substituted alkenes are then presented in a more detailed manner, with a special focus on chemo- and stereoselectivity problems. The reduction of aromatic systems is presented, and new advances in hydrogenation (heterogeneous and homogeneous) methods, as well as the recent progress in dissolving metal reductions, are described, including the chemo- and stereoselectivity aspects. Recent reports on hydride and electrochemical reductions are then presented. Finally, the reduction of alkynes and allenes is briefly discussed.