Preparation of enol ester epoxides and their ring-opening to α-silyloxyaldehydes

The Z-selective ruthenium-catalyzed addition of aromatic carboxylic acids to alkynes was followed by dioxirane epoxidation to furnish enol ester epoxides with cis configuration. Upon treatment of enol ester epoxides with tert-butyldimethylsilyl triflate in the presence of 2,6-lutidine, synthetically useful α-silyloxyaldehydes were obtained. This novel transformation was facilitated by microwave irradiation.