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Abstract:
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Hydrogen gas is the cleanest and most cost -effective reductant available to mankind , and the use of hydrogen gas in catalytic hydrogenation reactions is one of the oldest and most utilized organic reactions . Although catalytic hydrogenation has been practiced in industry on enormous scale , the use of hydrogen gas as a terminal reductant in C -C bond forming reactions has been limited to processes involving the migratory insertion of carbon monoxide such as : alkene hydroformylation and the Fischer -Tropsch reaction . A significant advance to the field of synthetic organic chemistry would be the expansion of C -C bond forming reactions beyond reductive coupling via carbon monoxide insertion . Herein , related metal catalyzed reductive couplings to [alpha] ,[beta] -unsaturated compounds in the presence of reducing agents such as : silane , borane , and hydrogen are reviewed . The following chapters discuss the development of hydrogen -mediated reductive aldol and Mannich reactions . The results from this body of work clearly demonstrate that hydrogen -mediated C -C bond forming reactions are emerging as a powerful tool for synthetic chemists . |