Brønsted Acid Catalyzed Formation of Enynes

Significance

Conjugated enynes are useful building blocks in organic synthesis, thus regio- and stereoselective methods for their formation are of interest. Ring opening of 1-cyclopropyl-2-propyn-1-ols (1) with heteroatom nucleophiles to provide conjugated enynes has been previously reported with gold, ruthenium, and ytterbium catalysts. The authors report an efficient protocol for the ring opening of 1 employing a Brønsted acid catalyst.