Practical Synthesis of Four Stereoisomers of 6-(t-Butyldiphenylsiloxy)-3,5-dimethyl-1- (triphenylmethoxy)hexane-2,4-diol via Dithiane Coupling with Oxirane.

The anion derived from 2-substituted 1,3-dithiane derivative, (S)-2-[2-(t-butyldiphenylsiloxy)-1-methylethyl]-1,3-dithiane, with n-BuLi at room temperature (r.t.) in THF was subjected to coupling with 2,3-disubstituted oxirane, (2S,3S)- or (2S,3R)-2,3-epoxy-1-(triphenylmethoxy)butane, at r.t., giving the coupling products in satisfactory yield. These coupling products were subjected to de-dithioacetalization, and the resulting carbonyl compounds were stereoselectively reduced to afford four stereoisomers of 6-(t-butyldiphenylsiloxy)-3,5-dimethyl-1-(triphenylmethoxy)hexane-2,4-diol.