Acetic Acid Mediated Sulfonylation of Allenylphosphine Oxides: Divergent Synthesis of Bifunctionalized 1,3-Butadienes and Allenes.

An acetic acid-mediated sulfonylation of allenylphosphine oxides with sodium sulfinates is disclosed. This new methodology involves tandem (Ar)O-C(sp3) bond cleavage and C(sp2)/C(sp3)-SO2 formation toward divergent synthesis of sulfonyl- and phosphinyl-bifunctionalized 1,3-butadienes or allenes, depending on the substitution at the terminal carbon atoms of allenylphosphine oxides. The reaction mechanism is explained via an acid-accelerated synergistic process.