One-Step Addition of Sulfonic Acids to Acetylene Derivatives: An Alternative and Stereoselective Approach to Vinyl Triflates and Fluorosulfonates.

Acetylenic acids and esters as well as acetylenic ketones were efficiently and stereoselectively converted in one step to the corresponding vinyl triflates or fluorosulfonates in triflic or fluorosulfonic acids. Depending on the reaction conditions the E or the Z isomer can be obtained very conveniently in high isolated yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)