Highly Efficient One-Pot Access to Functionalized Arylboronic Acids via Noncryogenic Bromine/Magnesium Exchanges

Timo Leermann , Frédéric Leroux (1) , Francoise Colobert-Leuenberger (1)

1 LIMA - Laboratoire d'innovation moléculaire et applications

A general and convenient protocol for the electrophilic borylation of aryl Grignard reagents prepd. from arylbromides by direct insertion of Mg in the presence of LiCl or by Mg/Br exchange with iPrMgCl·LiCl was developed. Various aryl boronic acids were synthesized in a straightforward manner in excellent yields at 0°. E.g., reaction of mixt. of 4-bromoanisole, Mg turnings, LiCl in THF with DIBAL-H catalyst followed by the addn. of trimethylborate at 0° gave 92% yield of 4-MeOC6H4B(OH)2.

Domaines: Chimie organique

Timo Leermann, Frédéric Leroux, Francoise Colobert-Leuenberger. Highly Efficient One-Pot Access to Functionalized Arylboronic Acids via Noncryogenic Bromine/Magnesium Exchanges. Organic Letters, 2011, 13 (17), pp.4479-4481. ⟨10.1021/ol2016252⟩. ⟨hal-02305220⟩