Water-Triggered, Counter-Anion-Controlled; and Silver—Phosphines Complex-Catalyzed Stereoselective Cascade Alkynylation/Cyclization of Terminal Alkynes with Salicylaldehydes.

A highly efficient alkynylation-cyclization of terminal alkynes with salicylaldehydes leading to substituted 2,3-dihydrobenzofuran-3-ol derivatives was developed by using Cy3P-silver complex as catalyst in water. Counter anions in the silver complex proved to be the key factor to Z/E stereoselectivity control. Aurones can also be obtained effectively from the cascade reaction followed by oxidation without further purification. [ABSTRACT FROM AUTHOR]