Catalytic Allylation of Hypophosphorous Acid and H-Phosphinic Acids with Primary Allylic Amines

Primary allylic amines serve as suitable allylic electrophiles for the allylation reactions of hypophosphorous acid and H-phosphinic acids. In the presence of tris(dibenzylideneacetone)dipalladium(0) ([Pd-2(dba)(3)], 0.1 mol %) and Xantphos (0.2 mol %), aqueous hypophos-phorous acid was allylated by alpha-unbranched primary allylic amines in a highly regioselective fashion to give structurally diverse allylic H-phosphinic acids in good to excellent yields with exclusive E selectivity. Moreover, increasing the catalyst loading to 1 mol % and adding aqueous phosphoric acid (1.2 equiv.) permitted the allylation of H-phosphinic acids with alpha-unbranched primary allylic amines to proceed to give disubstituted phosphinic acids in good to excellent yields.