Ag(I)-catalyzed cyclization reaction of ethyl o-hydroxyphenylethynylphosphinates to phosphachromones

An Ag(I)-catalyzed intramolecular cyclization of ethyl o-hydroxyphenylethynylpho-sphinate to phosphachromones has been developed with high regioselectivity and good yields. The present reaction represents the first example of intramolecular addition of phenol to 1-alkynylphosphonates, which provides an approach to synthesize new phosphorus heterocycles. The resulting phosphachromones could have potential bioactivities.