Ni(0)-Catalyzed Dimerization of o-Keto Carboxylic Acid Pseudochlorides

Abstract

A new protocol of the synthesis of 3,3′-diaryl-3,3′-diphthalides by dehalogenation of o-keto carboxylic acid pseudochlorides is implemented. The feature of the new protocol is that the reaction is carried out in the presence of a zero-valent nickel complex catalyst generated in situ by mixing zinc powder, nickel(II) chloride, triphenylphosphine, and 2,2′-bipyridine. Along with the target dimerization products of pseudochlorides, minor products were isolated, whose structure allowed to propose possible schemes of side reactions.