Kinetische und mechanistische Untersuchungen von Uebergangsmetall-Komplex-Reaktionen. XXV. Ungewoenlich leicht ablaufende intermolekulare Kupplung von CO und dem Carben-Liganden bei neutralen Carben-Komplexen des Typs (CO)5W=C(Aryl)H

Article abstract of DOI:10.1016/0022-328X(89)85314-8

The benzylidene(pentacarbonyl)tungsten complexes (CO)5W (II) (R=H (a), Me (b)) react with CO (1 bar) in CH2Cl2 in the presence of MeOH even at low temperature to give arylacetic acid methyl esters, (C6H4R-p)CH2COOMe (VI).The yield of VI increases CO pressure.External 13CO is incorporated into the ester.A direct attack of free CO on the electrophilic benzylidene carbon atom of II with the formation of a coordinated ketene in the initial reaction step is proposed.