Gold‐Catalyzed Chemoselective Synthesis of Heterocycles from 3‐(2‐Azidophenyl)prop‐2‐yn‐1‐ols and Aldehydes

An efficient method to prepare 6-(2-azidophenyl)-4H-1,3-dioxins and 4,5-dihydro[1,3]dioxino[5,4-b]indoles by gold-catalyzed tandem-annulation of 3-(2-azidophenyl)prop-2-yn-1-ols with aldehydes was examined. The reactions afforded the products in moderate to excellent yields under mild reaction conditions. Uniquely, the reactions proceeded with complete control of product chemoselectivity for a variety of 3-(2-azidophenyl)prop-2-yn-1-ols in the presence of 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenylgold(I) bis(trifluoromethanesulfonyl)imide (XPhosAuNTf2).