Synthesis of Functionalized Benzofurans from para-Quinone Methides via Phospha-1,6-Addition/O-Acylation/Wittig Pathway.

An efficient synthesis of functionalized benzofurans is achieved under mild and metal-free conditions from stable para-quinone methides by treatment with phosphine, acyl chloride, and a base. This one-pot phospha-1,6-addition/O-acylation/Wittig reaction is also demonstrated under catalytic conditions with similar efficacy.