Synthesis of 1',3'-dioxolan-2'-one by the reaction of steroidal oxiranes with carbon dioxide: Synthesis of five-membered cis cyclic carbonates

摘要

The reaction of 3-acetoxy-5,6-epoxy-5-cholestane 1, its 3-chloro analogue 2, and 5,6-epoxy-5-cholestane 3 with carbon dioxide gas in the presence of sodium bromide as catalyst with continuous stirring at 100C for 30min affords selectively the corresponding 1',3',-dioxolan-2'-ones (steroidal cyclic cis-carbonates) 4-6 in excellent yields. The structures of these products have been established on the basis of their elemental analysis and spectral data (infrared, ~1H NMR, and mass).