Twofold Unsymmetrical C—H FunctionalizatiOn of PyrDipSi-Substituted Arenes: A General Method for the Synthesis of Substituted meta-Halophenols

摘要

Transition-metal-catalyzed heteroatom-directed C-H func-tionalization of arenes has emerged as a powerful and environmentally benign tool for carbon-carbon and carbon-heteroatom bond formation. Moreover, twofold aromatic C-H functionalization is synthetically even more appealing as it allows for the introduction of two substituents in a one-pot or a two-step procedure. However, twofold C—H functionalization has been used only for the introduction of the same (e.g. alkenyl/alkenyl, aryl/aryl, OR/OR, Hal/Hal; Scheme 1 A, I) or similar functionalities (e.g. alkenyl/alkenyl', OAc/OPiv (Piv = pivaloyl), Cl/Br; Scheme 1 A, II).