Enantioselective synthesis of polycyclic ketones by desymmetrisation of bis(phenylsulfonyl)alkenes with chiral alcoholates. Control of the absolute configuration by a simple modification of the chiral auxiliary

Article abstract of DOI:10.1016/S0040-4039(99)01848-1

Treatment of polycyclic bis(phenylsulfonyl)alkenes with chiral alcoholates, followed by acidic work-up, affords enantioselectively α-phenylsulfonyl ketones. The enantioselectivity is total with monomethylated hydrobenzoin and of opposite configuration with respect to that obtained with hydrobenzoin itself. Thus, starting from a bis(phenylsulfonyl)alkene, it is possible to obtain either the R or S polycyclic ketone by the use of the same chiral auxiliary (hydrobenzoin) and a simple modification (methylation of one of the hydroxy functions).