Tin-catalyzed hydrophosphination of alkenes.

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.