Photoinduced cobaloxime catalysis enabled dehydrogenative C2-phosphinylation of bicyclo[1.1.0]butanes to access phosphorylated cyclobutenes.

A photoinduced ring-opening radical C2-phosphinylation of bicyclo[1.1.0]butanes with secondary phosphine oxides by cobaloxime catalysis is described. This reaction features mild conditions, wide substrate scope, and high site-selectivities, producing a diverse range of phosphorylated cyclobutenes in good yields with hydrogen evolution. The mechanism studies indicate that this reaction likely proceeds through a bicyclo[1.1.0]butane isomerization and dehydrogenative allylic phosphinylation process.