Flash Communication: A Lewis Acidity-Diminished, Stable Diborylethyne

Abstract

The synthesis and reactivity of (dan)BC≡CB(dan), a previously untapped diborylethyne characterized by remarkably diminished Lewis acidity are reported. In contrast to Lewis acidic analogues that decompose upon exposure to water, the dan-substituted diborylethyne exhibits exceptional stability toward air, moisture, and silica gel chromatography. We further demonstrate the utility of the central triple bond as a robust platform for diverse catalytic transformations, providing access to multimetalated alkenes. The significant disparity in Lewis acidity between B(dan) and B(pin) moieties enables precise, chemoselective Suzuki–Miyaura cross-couplings, allowing for the modular construction of multisubstituted alkenes while leaving the B(dan) groups intact.