Late Stage Functionalization of 1,2-Azaborines for Application in Biomedical Research

Abstract

Chapter 1. Use of boron as a pharmacophore is as growing but still underdeveloped strategy for expanding chemical space in biomedical research. In addition to more established methods of incorporating boron in drug development, an attractive and emerging method of introducing boron into biologically active compounds is through boron-nitrogen containing heterocycles. In particular, the Liu group has focused on exploring the interactions of monocyclic 1,2-azaborines in biological space. In order to install complicated chemical functionality needed for further studies, methods for late stage functionalization of 1,2-azaborines must be developed. Described herein is a method for functionalizing 1,2-azaborine at the C3- and C5-positions, with bromine and iodine handles, respectively. Chapter 2. Described is the application of the turbo Grignard reaction to 1,2-azaborines bearing a B–Cl bond. The reaction utilizes iPrMgCl·LiCl to form aryl carbon nucleophiles and is tolerant of sensitive functional groups such as nitriles and esters. Development of the reaction obviates the need to use toxic organotin reagents to install aryl groups at the B-position that bear sensitive, electrophilic functionalities.