Palladium-catalyzed decarboxylative cycloaddition of vinylethylene carbonates with formaldehyde: enantioselective construction of tertiary vinylglycols.

An efficient method for the enantioselective construction of tertiary vinylglycols through a palladium-catalyzed asymmetric decarboxylative cycloaddition of vinylethylene carbonates with formaldehyde was developed. By using a palladium complex generated in situ from [Pd2(dba)3]⋅CHCl3 and a phosphoramidite ligand as a catalyst under mild reaction conditions, the process allows conversion of racemic 4-substituted 4-vinyl-1,3-dioxolan-2-ones into the corresponding 1,3-dioxolanes, as methylene acetal protected tertiary vinylglycols, in high yields with good to excellent enantioselectivities.