Ethyl‐β‐chlorovinyl ether

The preparation of ethyl‐β‐chlorovinyl ether from the readily available dichloroacetal is reported. Careful fractionation of the product yields the pure cis‐ and trans‐isomers of which only the cis‐isomer gives a high yield (76%) of ethoxy‐acetylene on heating with potassium hydroxide. The corresponding ethyl‐β‐bromovinyl ether has likewise been separated into cis‐ and trans‐isomers.