Nickel (0) -Catalyzed Reaction of Acetylenic Compounds with Carbon Dioxide and Aldehydes.

Abstract

Transition metal-catalyzed carbon dioxide fixation into unsaturated hydrocarbons is an important problem. On the basis of two new approaches, i.e., use of reactive substrates of diynes and alkoxyacetylenes and synthesis of a trialkylphosphine ligand containing a pyridyl functional group, we have developed an efficient and selective nickel (0) -catalyzed cycloaddition reaction of acetylenes with carbon dioxide to various 2-pyrones. By the use of aldehydes instead of carbon dioxide, we have also developed a nickel (0) tertiary phosphine complex-catalyzed reaction of diynes and monoynes with aldehydes, which provides synthetic methods of bicyclic 2H-pyrans, functionalized carbo and heterocycles and α, β-enones.