Organoiron- and Fluoride-Catalyzed Phosphinidene Transfer to Styrenic Olefins in a Stereoselective Synthesis of Unprotected Phosphiranes.

Catalytic phosphiranation has been achieved, allowing preparation of -1-R-2-phenylphosphiranes (R = -Bu: --Bu; -Pr: --Pr) from the corresponding dibenzo-7-(R)-7-phospha-norbornadiene (RP, = CH, anthracene) and styrene in 73% and 57% isolated yields, respectively. The cocatalyst system requires tetramethylammonium fluoride (TMAF) and [Fp(THF)][BF] (Fp = Fe(η-CH)(CO)). In the case of the -Bu derivative, the reaction mechanism was probed using stoichiometric reaction studies, a Hammett analysis, and a deuterium labeling experiment. Together, these suggest the intermediacy of iron-phosphido FpP(F)(-Bu) (), generated independently from the stoichiometric reaction of [Fp(-BuP)][BF] with TMAF. Two other plausible reaction intermediates, [Fp(-BuP)][BF] and [Fp(--Bu)][BF], were prepared independently and structurally characterized.