New 6-oxa-2-silabicyclo[2.2.0]hexanes by photochemical conversion of acyl(allyl)(dimethyl) silanes

Under UV irradiation in acetonitrile, acyl(allyl) silanes undergo an intramolecular (2+2) cycloaddition (Paterno-Buchi type reaction) to give unprecedented 1-alkyl-6-oxa-2-silabicyclo[2.2.0] hexanes.