Gold(I)-Catalyzed Hydration of Alkynylphosphonates: Efficient Access to β-Ketophosphonates

A general, efficient, and highly regioselective protocol with the use of a gold(I) complex catalytic system for the transformation of alkynylphosphonates into the corresponding β‐ketophosphonates has been successfully developed. This method produces a variety of β‐ketophosphonates with the advantages of mild reaction conditions, high functional‐group tolerance, and excellent yields. An efficient and mild gold‐catalyzed hydration process for the regioselective synthesis of β‐ketophosphonates directly from alkynylphosphonates is described. Twenty‐two examples with yields of 85–97 % are reported. Different substituents including substituted aryl, alkyl, chloro, ester, sulfonoxyl, and phthalimide groups are tolerated; XPhos = 2‐dicyclohexylphosphino‐2′,4′,6′‐triisopropylbiphenyl, Tf = trifluoromethylsulfonyl.