Raffaella Volpicelli

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

Abstract 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).

Li+ and Na+ switch of enantioselectivity in the desymmetrisation of polycyclic bis(phenylsulfonyl)alkenes by chiral alcohols

A complete switch of enantioselectivity is obtained in the desymmetrisation reaction of polycyclic bis(phenylsulfonyl)alkenes by the change of the base from n-BuLi to NaH, thus allowing convenient access to either enantiomer of polycyclic ketones with the same chiral auxiliary.

Synthesis of New Active o‐Nitrophenyl Carbamates

Abstract A very high‐yielding reaction of bis(o‐nitrophenyl) carbonate with aliphatic amines under mild conditions has been developed. The resulting o‐nitrophenyl carbamates were characterized by IR, 1H‐NMR, 13C‐NMR, and elemental analysis.