Functional carbonates: cyclic α-methylene and β-oxopropyl carbonates from prop-2-ynyl alcohol derivatives and CO 2

The phosphine-catalysed synthesis of cyclic α-methylene carbonates 2 directly from prop-2-ynyl alcohol derivatives and CO2 is described. These cyclic carbonates 2 are key intermediates for the selective access to β-oxopropyl carbonates 3 by reaction with alcohols under mild conditions, but in the presence of Et2N or KCN as catalyst.