Photoinduced Vitamin-B₁₂-Catalyzed meta-C–H Bromination/Chlorination of Phenol Derivatives Assisted by a U-Shaped Nitrile Template

Abstract

A photoinduced vitamin-B 12 -catalyzed meta-C−H bromination/chlorination of phenol derivatives was established using a nitrile directing template and N-bromosuccinimide (NBS)/N-chlorosuccinimide (NCS) as halogenated reagents, and a series of meta-bromination/chlorination products were obtained in yields of 51 to 80%. This strategy overcame the selectivity problem of phenols, which have difficulty obtaining meta-products through conventional electrophilic reactions. Furthermore, natural product resveratrol and an intermediate of the γ-secretase inhibitor were successfully synthesized, which demonstrates the practicability of this method.