CuX2-mediated halolactonization reaction of monoesters of 1,2-allenyl phosphonic acids and their Suzuki cross-coupling reaction.

CuX(2)-mediated (X = Cl, Br) halolactonization of monoesters of 1,2-allenyl phosphonic acids is presented. The reaction proceeded smoothly under the mild condition for differently substituted allenic substrates giving the 4-halo-2,5-dihydro[1,2]oxaphosphole 2-oxides in good yields. The Suzuki cross-coupling reaction of these bromides and even chlorides with organic boronic acids under the catalysis of PdCl(2)(Sphos)(2) afforded 4-substituted-2,5-dihydro[1,2]oxaphosphole 2-oxides in moderate to good yields.