Seoul National University · Chemistry
Professor Hong Geun Lee's research lab specializes in the development of innovative transition-metal-catalyzed and electrochemically mediated methodologies for selective C–H and C–X bond functionalization, with a strong focus on synthetic methodology for complex molecule synthesis and radiolabeling. The lab pioneers mild, selective, and operationally simple transformations—particularly Pd-catalyzed fluorination, arylation of unprotected peptides, and radiosynthesis of (11)C-labeled pharmaceuticals—enabling applications in drug discovery and positron emission tomography (PET) imaging. A central theme is the design of robust, well-defined catalysts and precatalysts that enable challenging transformations under ambient conditions with high functional group tolerance and selectivity. The lab also explores fundamental reactivity patterns in sp³-hybridized carbon functionalization, leveraging electrochemical strategies to access reactive intermediates for diverse heteroatom incorporation.
Figures are computed from collected data and may differ slightly.
On the basis of mechanism-driven reaction design, a Pd-catalyzed nucleophilic fluorination of aryl bromides and iodides has been developed. The method exhibits a broad substrate scope, especially with respect to nitrogen-containing heteroaryl bromides, and proceeds with minimal formation of the corresponding reduction products. A facilitated ligand modification process was shown to be critical to the success of the reaction.
The stable Pd(0) species [(1,5-cyclooctadiene)(L·Pd)2] (L = AdBrettPhos) has been prepared and successfully evaluated as a precatalyst for the fluorination of aryl triflates derived from biologically active and heteroaryl phenols, challenging substrates for our previously reported catalyst system. Additionally, this precatalyst activates at room temperature under neutral conditions, generates 1,5-cyclooctadiene as the only byproduct, and leads to overall cleaner reaction profiles.
A mild method for the arylation of lysine in an unprotected peptide is presented. In the presence of a preformed biarylphosphine-supported palladium(II)-aryl complex and a weak base, lysine amino groups underwent C-N bond formation at room temperature. The process generally exhibited high selectivity for lysine over other amino acids containing nucleophilic side chains and was applicable to the conjugation of a variety of organic compounds, including complex drug molecules, with an array of pept
A new radiosynthetic protocol for the preparation of [(11)C]aryl nitriles has been developed. This process is based on the direct reaction of in situ prepared L·Pd(Ar)X complexes (L = biaryl phosphine) with [(11)C]HCN. The strategy is operationally simple, exhibits a remarkably wide substrate scope with short reaction times, and demonstrates superior reactivity compared to previously reported systems. With this procedure, a variety of [(11)C]nitrile-containing pharmaceuticals were prepared with
Based on systematic electrochemical analysis, an integrated synthetic platform of C(sp<sup>3</sup>)-based organoboron compounds was established for the introduction of heteroatoms. The electrochemically mediated bond-forming strategy was shown to be highly effective for the functionalization of sp<sup>3</sup>-hybridized carbon atoms with significant steric hindrance. Moreover, virtually all the nonmetallic heteroatoms could be utilized as reaction partners using one unified protocol. The observe
A full carbon skeleton of the natural product lomaiviticin has been synthesized. The approach features anionic annulation reactions to deliver A and B rings of the natural product, and stereoselective oxidative enolate coupling to form the central C2C2′ σ bond. In the course of the investigation, a remarkable substituent effect at C11 position was observed. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not cop
Abstract A mild method for the arylation of lysine in an unprotected peptide is presented. In the presence of a preformed biarylphosphine‐supported palladium(II)–aryl complex and a weak base, lysine amino groups underwent C−N bond formation at room temperature. The process generally exhibited high selectivity for lysine over other amino acids containing nucleophilic side chains and was applicable to the conjugation of a variety of organic compounds, including complex drug molecules, with an arra
A novel reactivity toward C-F bond functionalization has been developed, which could be designated as fluorine atom transfer (FAT). A photoexcited state of an <i>N</i>-heterocyclic carbene-ligated boryl radical exhibits a transcendent reactivity, capable of activating chemically inert carbon-fluorine bonds through homolysis. Combined experimental and computational studies suggest that the ligated boryl radical species directly abstracts a fluorine atom from the organofluoride substrates to provi
A novel strategy for the stereospecific Pd-catalyzed acylative cross-coupling of enantiomerically enriched alkylboron compounds has been developed. The protocol features an extremely high level of enantiospecificity to allow facile access to synthetically challenging and valuable chiral ketones and carboxylic acid derivatives. The use of a sterically encumbered and electron-rich phosphine ligand proved to be crucial for the success of the reaction. Furthermore, on the basis of experimental and c
A mechanistically unique functionalization strategy for a benzylic C(sp<sup>3</sup>)-H bond has been developed based on the facile oxidation event of indole substrates. This novel pathway was initiated by efficient radical generation at the benzylic position of the substrate, with subsequent transition metal catalysis to complete the overall transformation. Ultimately, an aryl or an acyl group could be effectively delivered from an aryl (pseudo)halide or an acid anhydride coupling partner, respe
Reported herein is a novel reaction engineering protocol to enhance the efficiency of a transition metal-catalysed process by strategically preventing ligand degradation. Based on spectroscopic investigations, a decomposition pathway of a chiral phosphoramidite ligand during a Cu-catalysed reaction was identified. The involvement of the destructive process could be minimized under the modified reaction conditions that control the amount of nucleophilic alkoxide base, which is the origin of ligan
A single-electron transfer mediated modular indole formation reaction from a 2-iodoaniline derivative and a ketone has been developed. This transition-metal-free reaction shows a broad substrate scope and unconventional regioselectivity trends. Moreover, important functional groups for further transformation are tolerated under the reaction conditions. Density functional theory studies reveal that the reaction proceeds by metal coordination, which converts a disfavored 5-<i>endo-trig</i> cycliza
A synthetic strategy for the formation of C(sp<sup>3</sup>)-N bonds, particularly through a copper-catalyzed oxidative cross-coupling, is rare. Herein, we report a novel synthetic approach for the preparation of tertiary sulfonamides via copper-catalyzed intra- and intermolecular oxidative C(sp<sup>3</sup>)-N cross-coupling reactions. This method allows the utilization of the readily available C(sp<sup>3</sup>)-based pinacol boronate as a substrate and the tolerance of a wide range of functional
A novel mechanistic duality has been revealed from the indolyl 1,3-heteroatom transposition (IHT) of <i>N</i>-hydroxyindole derivatives. A series of in-depth mechanistic investigations suggests that two separate mechanisms are operating simultaneously. Moreover, the relative contribution of each mechanistic pathway, the energy barrier for each pathway, and the identity of the primary pathway were shown to be the functions of the electronic properties of the substrate system. Based on the mechani
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