On the mechanism and regioselectivity of alkane photocarbonylation catalyzed by Rh(PMe3)2(CO)Cl

Article abstract of DOI:10.1016/0022-328X(95)05603-M

Photochemical carbonylation of hexane catalyzed by Rh(PMe3)2(CO)Cl (1) is found to proceed via at least two different mechanisms.One requires a secondary photochemical reaction and gives primarily (ca. 98percent) linear aldehyde, while the other is radical-based, much less regioselective, and apparently involves only one photochemical step.In accord with this mechanistic understanding, it has proven possible to find conditions leading simultaneously to high photoefficiency and regioselectivity, and greatly increased chemical yields.The presumed photointermediate in the two-photoprocess pathway has been photochemically generated at low temperature and characterized by NMR spectroscopy. Keywords: Rhodium; Alkane activation; Carbonylation; Photochemistry