Preparation of novel polysubstituted chiral cyclohexanone derivatives containing a quaternary carbon by Ferrier reaction

2-C- and 3-C-[(2'-chloro)pyrid-5'-yl]-hex-5-enopyranosides were synthesized from 4,6-O-benzylidene acetals in three steps. By treatment with mercury or palladium salts, the corresponding cyclohexanones could be obtained. The stereochemistry of these reactions was highly dependent on the substitution pattern of the starting material and the nature and concentration of the catalyst.