Abstract
The α,β‐unsaturated thiolesters listed in Table I have been prepared by treating a mixture of a carbonyl compound and boron trifluoride with an acetylenic thioether (see reaction scheme 2). Good yields are obtained when ethers are used as solvents. The configuration of the esters prepared from aldehydes is trans. From unsymmetrical ketones mixtures of cis and trans isomers are formed.