Tin-catalyzed hydrophosphination of alkenes

Abstract

Simple tin derivatives, Cp*₂SnCl₂ (1) and Ph₂SnCl₂ (2), catalyze the hydrophosphination of alkene substrates with diphenylphosphine. Competitive dehydrocoupling to give Ph₄P₂ was observed, but this side reaction can be mitigated when the catalysis is conducted under an H₂ atmosphere. Efforts to prepare stable tin bis(phosphido) compounds commonly resulted in decomposition to Ph₄P₂. Lewis acidic inorganic tin compounds do not show dehydrocoupling reactivity. It was found that the Lewis acid, B(C₆F₅)₃, is able to engage in the hydrophosphination of alkenes, but it is poorly effective under the conditions tested.