Functionalization of Alkynes Catalyzed by t‐Bu‐P4 Base

The addition of O‐ and N‐nucleophiles to alkynes catalyzed by a phosphazene base, t‐Bu‐P4 base, was investigated. Alkynes were easily transformed to enol ethers and enamines in DMSO by the addition of nucleophiles. When phenylacetylene was reacted with diisopropylamine, a unique head‐to‐head dimerization of phenylacetylene was observed to give the enyne derivative. Terminal proton of phenylacetylene was also catalytically activated by t‐Bu‐P4 base to generate the acetylide anion which was reacted with carbonyl compounds to give phenylpropargylic alcohol derivatives.