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Short Paper | Regular issue | Vol 89, No. 12, 2014, pp.2739-2744
Published online, 17th November, 2014
DOI: 10.3987/COM-14-13098
A Practical and Scalable Process for the Preparation of 4-Aminophenylboronic Acid Pinacol Ester

Feng Xue,* Chang-Gong Li, Yong Zhu, Tian-Jun Lou, and Guang-Jie He*

*Key Laboratory of Functional Organic Molecules of Xinxiang City Henan Province, College of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang Henan, 453002, China

Abstract

A practical process has been developed for scalable preparation of 4-aminophenylboronic acid pinacol ester through facile two-step procedure. After boron trifluoride etherate efficiently activated the reaction of 4-bromoaniline with diphenyl ketone, metalation reaction of protected 4-bromoaniline with lithium trialkylmagnesiate readily proceeded under mild conditions (−20 °C), which was subsequently subjected to esterification and deprotection reaction to give the 4-aminophenylboronic acid pinacol ester. The improved synthetic route has been successfully scaled up to kilogram quantities in good yield and high quality.