Researchers at UNIST have introduced a new chemical methodology that employs cost-effective nickel catalysts to achieve site-selective boron addition to alkynes. This breakthrough significantly broadens the repertoire of molecular modifications, with promising implications for pharmaceutical development and advanced material synthesis.
Led by Professors Sung You Hong and Jan-Uwe Rohde from the Department of Chemistry, the team focused on terminal alkynes—molecules characterized by a triple bond at one end. Their innovative approach selectively activates and cleaves the triple bond, enabling boron atoms to be introduced internally, rather than at the terminal position. The resulting products can subsequently be transformed into a diverse array of functional compounds.
The process involves the controlled cleavage of the alkyne’s triple bond facilitated by nickel, which transiently binds to the substrate, directing boron attachment to the internal carbons. Once boron is installed, nickel is released, leaving a boron-containing moiety primed for further synthetic elaboration. This highly regioselective strategy broadens the scope for constructing complex molecular architectures with precision.
Application of this methodology to the modification of various substrates—including derivatives of the anticancer agent bexarotene and analogs of pargyline—demonstrates its versatility and potential to streamline the synthesis of pharmaceutical compounds. By enabling targeted modifications, this technique could accelerate the development of new drug candidates and lead to more efficient drug synthesis pathways.
Central to the mechanistic understanding of the reaction were the detection and characterization of fleeting nickel intermediates, achieved through electron paramagnetic resonance (EPR) spectroscopy and high-resolution mass spectrometry. Complementary computational studies elucidated the stabilizing noncovalent interactions underlying the reactions’s regioselectivity, providing valuable insights into its driving forces.
First authors Jeong Woo Lee, Gun Ha Kim, and Seo Yeong Jeong played key roles in the research. Professor Rohde remarked, “The products of a catalytic reaction rarely reveal the route it took. By catching these short-lived nickel intermediates, we could map the reaction pathway to the site where boron is added. This approach gives chemists a more rational basis for designing new catalysts.”
Professor Hong emphasized the broader significance, noting “The value of nickel here is not only that it is abundant and inexpensive. It lets us control a difficult reaction at a specific site, turning simple alkynes into building blocks that can be used to make medicines and organic materials.”
The study was published in ACS Catalysis on April 17, 2026, and supported by the Basic Science Research Program and the ERC Project (Engineering Research Center for Microplastic through Bio/Chemical engineering Convergence Process) funded by the National Research Foundation of Korea (NRF).
Journal Reference
Jeong Woo Lee, Gun Ha Kim, Seo Yeong Jeong, et al., “Spectroscopic Evidence of a Reduced Alkenylnickel Intermediate in Catalytic Markovnikov-Selective Alkyne Hydroboration,” ACS Catal., 2026, 16, 7551-7561.
