Unique physicochemical and catalytic properties dictated by the B3NO2 ring system

Abstract

The expansion of molecular diversity beyond what nature can produce is a fundamental objective in chemical sciences. Despite the rich chemistry of boron-containing heterocycles, the 1,3-dioxa-5-aza-2,4,6-triborinane (DATB) ring system, which is characterized by a six-membered B₃NO₂ core, remains elusive. Here, we report the synthesis of m-terphenyl-templated DATB derivatives, displaying high stability and peculiar Lewis acidity arising from the three suitably arranged boron atoms. We identify a particular utility for DATB in the dehydrative amidation of carboxylic acids and amines, a reaction of high academic and industrial importance. The three boron sites are proposed to engage in substrate assembly, lowering the entropic cost of the transition state, in contrast with the operative mechanism of previously reported catalysts and amide coupling reagents. The distinct mechanistic pathway dictated by the DATB core will advance not only such amidations, but also other reactions driven by multisite activation.