Carbene complexes in organic synthesis: a new tungstacarbene-promoted alkyne insertion–olefin cyclopropanation reaction
Abstract
Carbene complexes of tungsten, bearing a co-ordinated double bond two carbons away from the carbene function, react with alkynes to give, after insertion of the alkyne, bicyclo[4.1.0]heptane derivatives as a result of cyclopropanation of the double bond by the newly formed carbene complex.