Zinc-Catalyzed Dual C-X and C-H Borylation of Aryl Halides

• Published in: Angewandte Chemie International Edition Vol. 54; no. 40; pp. 11843 - 11847
• Main Authors: Bose, Shubhankar Kumar, Deißenberger, Andrea, Eichhorn, Antonius, Steel, Patrick G., Lin, Zhenyang, Marder, Todd B.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 28-09-2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Activation; Aromatic compounds; Bonding; boronate esters; Catalysis; Catalysts; cross-coupling; CH activation; Halides; homogeneous catalysis; Hydrogen bonds; nitrogen heterocycles; Precursors; Radicals; Transformations; Zinc; cross-coupling; CH activation; boronate esters; homogeneous catalysis; nitrogen heterocycles
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201505603

A zinc‐catalyzed combined CX and CH borylation of aryl halides using B2pin2 (pin=OCMe2CMe2O) to produce the corresponding 1,2‐diborylarenes under mild conditions was developed. Catalytic CH bond activation occurs ortho to the halide groups if such a site is available or meta to the halide if the ortho position is already substituted. This method thus represents a novel use of a group XII catalyst for CH borylation. This transformation does not proceed via a free aryne intermediate, but a radical process seems to be involved.
Two B or not two B: A novel catalytic system based on a ZnII‐dtbpy precursor was developed for the preparation of 1,2‐diborylarenes. This method represents a new type of catalytic process for diborylation of aryl halides via both CX and CH activation.