Substituted Allyl Diphenylphosphine Oxides as Radical Allylating Agents

摘要

Following its discovery nearly a quarter of a century ago,[1] the radical allylation using allylstannanes has proved to be a very powerful synthetic tool. Numerous applications attest to the efficiency and compatibility of this methodology with a wide number of functional groups.[2] Nevertheless, the reaction suffers from some limitations, especially in respect to the substitution pattern around the allyl group. g-Substituted allylstannanes rapidly rearrange under the reaction conditions into their more stable a-isomers [Eq. (1)], and these were found to react mostly through abstraction of the allylic hydrogen atom [Eq. (2)] rather than by the desired addition fragmentation (Scheme 1).