Diastereoselective synthesis of 1,4-diaryl piperazines through the dimerization of 3-aminooxetanes with cooperative indium–diphenyl phosphate catalysis

A catalytic dimerization reaction of 3-aminooxetanes has been developed with cooperative indium/diphenyl phosphate catalysis, successfully achieving a [3 + 3] annulation reaction to provide a series of piperazine derivatives. The reaction features good functional group compatibility and excellent diastereoselectivity, enabling the synthesis of the corresponding piperazine products in moderate to good yields. The hydroxymethyl group present in the products could serve as a privileged moiety for diverse transformations, permitting the further elaboration of piperazine-based molecules.