Photochemical PCO-Group Transfer Provides P-Analogues of Beta-Lactams

Strategies to introduce phosphorus directly to hydrocarbon feedstocks would streamline the synthesis of organophosphorus compounds. Here, we demonstrate [2+2] cycloaddition between a pincer-supported nickel-phosphaethynolate (Ni–PCO) complex and olefins to afford oxophosphetanes, which are P-analogues of beta-lactams. The products are characterized by a suite of methods including multinuclear NMR spectroscopy supported by isotopic labeling experiments and micro-ED. A closed synthetic cycle for PCO-group transfer is demonstrated using TMS–PCO to liberate the P-heterocycle from Ni (TMS = trimethylsilyl). These results introduce a non-canonical reactivity mode for M–PCO complexes and broaden the available toolkit to incorporate phosphorus in hydrocarbon feeds.