A Universal Organocatalyst for Selective Mono-, Di-, and Triboration of Terminal Alkynes

Abstract

Multiboronate compounds are valuable synthetic building blocks for the construction of complex organic architectures via cross-coupling chemistry at the C–B bonds. Hence, there has been a tremendous amount of work in the past decades to develop practical multiboration reactions. Many of the developed methods start from alkynes, the most versatile synthetic precursors for multiboronates, and use transition-metal complexes as catalysts. However, several drawbacks such as low efficiency, poor selectivity, and narrow substrate and catalyst scopes remain major challenges to be addressed in this research area. Herein, we report the development of a universal organocatalytic system to promote the mono-, di-, and triboration of terminal alkynes in a highly efficient and selective manner. The reaction outcomes can be manipulated at will by varying the catalyst loading, reagent stoichiometry, and reaction time. A combined computational and experimental mechanistic study offers interesting insights into the selectivity of these sequential reactions.