Origins of Internal Regioselectivity in Copper-Catalyzed Borylation of Terminal Alkynes

02 June 2021, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Installation of a boron functionality into a more substituted carbon of terminal alkynes has been a challenging issue in chemical synthesis, since inherently Lewis acidic boron moieties, in principle, favor their attachment to a terminal carbon. Herein, we report on the highly internal-selective borylation of terminal alkynes under copper catalysis, wherein diminishment of boron-Lewis acidity and ligand-derived steric bulk around a copper center are the key to the success. In particular, the use of an anthranilamide-substituted boron moiety [B(aam)] is of high synthetic significance, because its properly diminished Lewis acidity enabled the internal regioselectivity and the Suzuki–Miyaura cross-coupling activity to be compatibly achieved. This method provided direct and universal approach to variously substituted branched alkenylboron compounds, regardless of electronic and steric properties of a substituent on terminal alkynes.


alkenylboron compounds
copper catalysis
internal selectivity
Lewis acidity
steric bulk effects
terminal alkynes

Supplementary materials



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