THE IN SITU GENERATION OF NON-STABILIZED CARBENE COMPLEXES VIA INTRAMOLECULAR ACETYLENE INSERTION: A NEW TWO-ALKYNE ANNULATION AND A NEW PREPARATION OF γ-KETO ESTERS

Article abstract of DOI:10.1016/S0040-4039(00)80110-0

Non-heteroatom stabilized carbene complexes can be generated in solution by mild thermolysis (50 deg C) of 4-hexynyl and 5-heptynyl (methoxymethylene) complexes of chromium and tungsten pentacarbonyl.These intermediates react with acetylenes to give a new type of two-alkyne annulation product.In the absence of acetylenes, these intermediates can be trapped with methanol as their carbonylated products which results in a new synthesis of γ-keto esters.