STEROIDS AND RELATED NATURAL PRODUCTS: XXXI. SELECTIVE REDUCTION OF ESTERS. PART B. CARBONATES

Abstract

Direct reduction of several pivalate esters to neopentyl ethers has been accomplished with boron trifluoride – sodium borohydride. The utility of the reduction reaction was illustrated with esters Ic, IIb, and IVa. Under the same conditions, a selection (Id, IId, and IVa) of carbonate esters was found to be relatively resistant to reduction. In this respect, the carbonate esters resembled benzoate esters, and selective reduction of a ketone (IId) or another ester (IVa → IVb) in their presence was possible. For comparison, one xanthate ester (Ie) was allowed to react with boron trifluoride – sodium borohydride, and only the corresponding alcohol (Ia) was isolated. Raney nickel desulfurization of xanthate Ia was shown to provide alcohol Ia and hydrocarbon If as principal products.