Attempted Kinetic Resolution Of 1,2-Diols By Camphorquinone - Generation Of (R)-(Chloromethyl)Oxirane

The epichlorohydrin (R)-(chloromethyl)oxirane has been prepared from rac-3-chloropropane-1,2-diol by means of the chiral ketone D-camphorquinone (1,7,7-trimethylbicyclo[2.2.1]heptane-2,3-dione). These reactions lead to intermediate dioxolanes which can be converted directly into oxiranes. This conversion was effected by reduction of the C-2-ketone of the dioxolane intermediate with sodium borohydride prior to reaction with hydrogen bromide-acetic acid followed by treatment of the resulting acetoxy bromide with sodium ethane-1,2-diolate. The diastereoselective formation of other dioxolanes was also investigated by reaction of D-camphorquinone with ethane-1,2-diol, propane-1,2-diol, and 3,3-dimethylbutane-1,2-diol.