https://scholar.dgist.ac.kr/handle/20.500.11750/56943 2026-06-03T23:37:05Z 2026-06-03T23:37:05Z Lee, Jeong Woo Kim, Gun Ha Jeong, Seo Yeong Jeon, Ji Hwan Kwon, Hyejin Kim, Yung Sam Jung, Byunghyuck Seo, Sangwon Rohde, Jan-Uwe Hong, Sung You https://scholar.dgist.ac.kr/handle/20.500.11750/60366 2026-05-28T18:01:17Z 2026-03-31T15:00:00Z

Title: Spectroscopic Evidence of a Reduced Alkenylnickel Intermediate in Catalytic Markovnikov-Selective Alkyne Hydroboration Author(s): Lee, Jeong Woo; Kim, Gun Ha; Jeong, Seo Yeong; Jeon, Ji Hwan; Kwon, Hyejin; Kim, Yung Sam; Jung, Byunghyuck; Seo, Sangwon; Rohde, Jan-Uwe; Hong, Sung You Abstract: Nickel-catalyzed hydrofunctionalization reactions, including the hydroboration of alkynes, have been generally proposed to proceed via classical two-electron pathways or, alternatively, through a NiIH-based insertion mechanism. Despite efforts to discern these pathways, explicit spectroscopic observation of NiIH species and relevant mechanistic information on LNiI(alkenyl) species remain lacking. Herein, we provide experimental evidence of formal NiI intermediates, suggestive of a NiIH-based insertion mechanism for alkyne hydroboration. The formation of a NiI catalyst precursor, LnNiI(dpm) (dpm = dipivaloylmethanate anion) and an LnNi(alkenyl) intermediate was confirmed by EPR spectroscopy and HRMS analysis. Their involvement in the catalytic reaction was demonstrated by stoichiometric and catalytic reactivity studies. The origin of the counterintuitive Markovnikov selectivity in the formation of the α-alkenylboronate product was probed by systematic ligand electronic effect studies. Computational analyses rationalize the selectivity by a kinetic preference for formation of the α regioisomer of the LnNi(alkenyl) intermediate through noncovalent interactions.

2026-03-31T15:00:00Z Lee, Yeonjoo Kim, Minseop Lee, Dohun Lee, Yunmi Seo, Sangwon Jung, Byunghyuck https://scholar.dgist.ac.kr/handle/20.500.11750/60350 2026-05-11T08:10:13Z 2026-02-28T15:00:00Z

Title: Cu-Catalyzed Stereo- and Regioselective Diborylation and trans-Protoborylation of 1,3-Enynes Author(s): Lee, Yeonjoo; Kim, Minseop; Lee, Dohun; Lee, Yunmi; Seo, Sangwon; Jung, Byunghyuck Abstract: As multifunctional chemical tools, organodiboron compounds present an important challenge in organic synthesis, with respect to their synthesis and functionalization. Although readily available 1,3-enynes have been employed as a platform for various regioselective difunctionalization reactions, the diborylation reactions of 1,3-enynes remain limited, and the installation of a CF3 group is often a prerequisite. In this study, we report a copper-catalyzed selective diborylation reaction of 1,3-enynes to access synthetically useful 1,1- and 1,4-diborylalkenes. The synthetic utility of this method is demonstrated by a gram-scale synthesis of a natural antifouling agent. Furthermore, the Cu-catalyzed trans-protoborylation reaction of aryl-substituted (Z)-enynes is reported. The thorough computational studies and the deuterium-labeling experiments provide insights into the reaction mechanism and the regio- and stereoselectivity of diborylated products.

2026-02-28T15:00:00Z Nam, Hyeontaek Jang, Seji Kim, Dongwook Seo, Sangwon https://scholar.dgist.ac.kr/handle/20.500.11750/60349 2026-05-11T18:01:13Z 2026-03-31T15:00:00Z

Title: NiH-Catalyzed Enantioconvergent α-Alkenylation of Carbonyl Compounds via Markovnikov Alkyne Hydronickellation Author(s): Nam, Hyeontaek; Jang, Seji; Kim, Dongwook; Seo, Sangwon Abstract: β-Methylene carbonyl motifs constitute privileged structural frameworks that play vital roles as a pharmacophore and serve as key intermediates in the assembly of architecturally complex molecules. Despite their synthetic importance, asymmetric approaches for their preparation remain scarce and are largely confined to substrate-controlled or stoichiometric chiral auxiliary methods. Herein, we report a nickel hydride-catalyzed enantioconvergent α-alkenylation of carbonyl compounds with alkynes, providing a direct and general route to α-chiral β-methylene carbonyl derivatives. The transformation proceeds via Markovnikov-selective alkyne hydronickellation followed by nickel-radical recombination to forge the α-stereogenic center, delivering the desired products with high levels of regio- and enantioselectivity. The protocol accommodates a wide range of alkynes and α-halocarbonyl partners, displays excellent functional group tolerance, and can be applied to the modification of biologically relevant molecules. Mechanistic investigations indicate that a partially protic Ni(II)H species governs the observed regioselectivity, while enantio-discrimination occurs during the radical capture step. This work establishes NiH catalysis as a versatile platform for expanding the synthetic repertoire for enantioenriched β-methylene carbonyl architectures. © 2026 The Author(s). Angewandte Chemie International Edition published by Wiley-VCH GmbH.

2026-03-31T15:00:00Z Baek, Seung Beom Kim, Youngho Lee, Wongyu Seo, Sangwon Kim, Dongwook Seo, Myungeun Chang, Sukbok https://scholar.dgist.ac.kr/handle/20.500.11750/59354 2026-01-13T18:01:09Z 2025-07-31T15:00:00Z

Title: Post-functionalization of polyethers by photoinduced C-H amidation via polar-radical relay Author(s): Baek, Seung Beom; Kim, Youngho; Lee, Wongyu; Seo, Sangwon; Kim, Dongwook; Seo, Myungeun; Chang, Sukbok Abstract: The C-H functionalization of polymers enables the direct incorporation of new functional groups into polymer backbones, presenting significant opportunities for the upcycling of commodity polymers. However, developing reactions that achieve selective functionalization while preserving the intrinsic features of polymers and avoiding undesirable structure deformation remains a considerable challenge. In this study, we present a transition metal-free post-functionalization approach for polyethers via a photoinduced alpha-C-H amidation reaction. This strategy provides a route to previously unattainable alpha-amino polyethers, which exhibit distinct physical properties from those of the parent polymer. By leveraging a polar-radical relay mechanism, we effectively incorporate C-N bonds into the polyether backbone while suppressing degradation and cross-linking. Conducted under mild and convenient conditions, this approach demonstrates significant site selectivity at the ethereal alpha-position, even in the presence of other types of C-H bonds, achieving tailed post-functionalization of macromolecules. Furthermore, the present strategy holds promise for broader applications, including the amidative degradation of commodity polymers and transformation of polyethylene glycol (PEG) network.

2025-07-31T15:00:00Z