Rhenium- and Manganese-Catalyzed Insertion of Alkynes into a Carbon-Carbon Single Bond of Cyclic and Acyclic 1,3-Dicarbonyl Compounds

Treatment of alkynes with cyclic and acyclic 1,3-dicarbonyl compounds in the presence of a catalytic amount of a rhenium or manganese complex gives ring-expanded and carbon-chain extension products, respectively. In these reactions, alkynes insert into a non-strained carbon-carbon single bond of 1,3-dicarbonyl compounds. The ring-expansion reaction is also promoted by the addition of 4-angstrom molecular sieves instead of a catalytic amount of an isocyanide.