Easy Access to Arylboron Dichloride and the Facile Synthesis of BN-containing Molecules

Abstract

Heteroatom incorporation is a general strategy for modulating the electronic properties of organic semiconducting materials. The isoelectronic substitutions of carbon–carbon (CC) bonds with boron–nitrogen (BN) bonds within molecules, in particular, enable the manipulation of the electronic properties without significant structural changes. A key step of the reaction to form BN bonds requires a halogenated boron reagent, such as arylboron dichloride, to react with an amine group. However, the commercially available arylboron dihalide lacks diversity compared with that of the corresponding arylboronic acid. Moreover, few methods of preparing arylboron dichloride are reported to date. Herein, we report a convenient synthetic protocol for the formation of various arylboron dichlorides using arylboronic acids with tetrachlorosilane. Using this method, we investigate BN annulation reactions of 2-ethynylaniline derivatives involving commercially available arylboronic acids. To further confirm the synthetic utility of this strategy, we demonstrate the straightforward, three-step synthesis of BN-ixene from readily accessible intermediates. Our simple, convenient method may promote the development of a wide range of BN-containing molecules.