摘要:
                                beta-Keto sulfoxides and beta-keto sulfones can be used as substrates for Mn(III)- and Cu(II)-based oxidative free-radical cyclizations.  The sulfoxide chiral center completely controls the stereochemistry of the cyclization.  Oxidative cyclization of racemic sulfoxide 8 affords 13 as a single diastereomer.  Oxidative cyclization of enantiomerically pure sulfoxide 20 gives 21 as a single enantiomer.  The chiral auxiliary can be removed by oxidation with potassium peroxomonosulfate to give the sulfone followed by reduction with sodium amalgam to give bicyclo[3.2.1]octanone 23.  Oxidative cyclization of 26 gives indanone 29, which spontaneously loses toluenesulfenic acid to give indenone 30.