Metal-free synthesis of chlorinated and brominated phosphinoyl 1,3-butadiene derivatives and its synthetic applications

Abstract

We report here an efficient and transition-metal free strategy for the synthesis of chlorinated and brominated phosphinoyl 1,3-butadienes and derivatives. Pre-prepared HCl/HBr solutions enabled the in situ rearrangement of phosphinoyl-α-allenic alcohols to conjugated vinyl cations, which afforded various novel polysubstituted phosphinoyl 1,3-butadienes in medium to excellent yields. The resulting products could be converted into multi-functionalized allylphosphine oxides; moreover, their couplings with electron-deficient arylboronic acid provided an efficient approach to synthesize electron-deficient phosphinoyl 1,3-butadienes.