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-Å molecular sieves instead of a catalytic amount of an isocyanide.