A NEW EFFICIENT AND SELECTIVE SYNTHESIS OF KETONES FROM ALKANES OR CYCLOALKANES, CO, AND SILANES IN THE PRESENCE OF APROTIC SUPERACIDS

A new approach to the direct synthesis of ketones from alkanes or cycl oalkanes (RH), CO, and silanes is proposed. Ketones were obtained in 5 0-97% yields from propane, butane, cyclopentane, cyclohexane, and meth ylcyclopentane on treatment with CO and silanes (Me4Si, Et4Si, or m- a nd p-XC6H4SiMe3, where X = Cl, Me, OMe) in the presence of CX4 . 2AlBr (3) (X = Br, Cl) superacids at 0 degrees C. The reactions with m- and p-XC6H4SiMe3 (X = Cl, Me) occur regioselectively to give m-ketones fro m m-silanes and p-ketones from p-silanes. However, the only product, p -MeOC6H4COR, is formed both from m- and P-MeOC6H4SiMe3. The reaction o f cyclo-C5H9CO+ with BzSiMe(3) results in an organosilicon ketone, Me3 SiCH2C6H4COC5H9, while in the presence of an excess of an acylating sy stem (after alcoholysis), Me2Si(OR')CH2C6H4COR is formed.