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A Visible‐Light‐Driven O ‐Glycosylation with Selenoglycosides Mediated by Chalcogen Bonding to Umemoto's Reagent

https://doi.org/10.1002/anie.202508424

Valenzuela, Erik_Alvarez; Duong, Tiffany; Pradeep, Vinayak; He, Xuxian; Dobson, Jacob_M; Lee, Semin; Lopata, Kenneth; Ragains, Justin_R (May 2025, Angewandte Chemie International Edition)

Abstract The activation of chalcogenoglycosides forO‐glycosylation typically involves strong electrophiles requiring low temperature. Herein, we demonstrate that visible‐light irradiation of selenoglycosides in the presence of Umemoto's reagent results in often high‐yieldingO‐glycosylation. We provide evidence that this process is mediated by a novel mode of reactivity, specifically photoinduced electron transfer within a chalcogen‐bonded complex.
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Scalable synthesis of [8]cycloparaphenyleneacetylene carbon nanohoop using alkyne metathesis

https://doi.org/10.1039/D1CC04776K

Zhou, Xin; Kwon, Hyejin; Thompson, Richard R.; Herman, Robert J.; Fronczek, Frank R.; Bruns, Carson J.; Lee, Semin (October 2021, Chemical Communications)

Large scale synthesis of cycloparaphenyleneacetylenes has been challenging due to low macrocyclization yields and harsh aromatization methods that often decompose strained alkynes. Herein, a cis -stilbene-based building block is subjected to alkyne metathesis macrocylization. The following sequence of alkene-selective bromination and dehydrobromination afforded a [8]cycloparaphenyleneacetylene derivative in high yield with good scalability. X-Ray crystal structure and computational analysis revealed a unique same-rim conformation for the eight methyl groups on the nanohoop.
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Siloxide Podand Ligand as a Scaffold for Molybdenum-Catalyzed Alkyne Metathesis and Isolation of a Dynamic Metallatetrahedrane Intermediate

https://doi.org/10.1021/acs.organomet.9b00430

Thompson, Richard R.; Rotella, Madeline E.; Du, Pu; Zhou, Xin; Fronczek, Frank R.; Kumar, Revati; Gutierrez, Osvaldo; Lee, Semin (October 2019, Organometallics)

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Impact of Ligands and Metals on the Formation of Metallacyclic Intermediates and a Nontraditional Mechanism for Group VI Alkyne Metathesis Catalysts

https://doi.org/10.1021/jacs.1c01843

Thompson, Richard R.; Rotella, Madeline E.; Zhou, Xin; Fronczek, Frank R.; Gutierrez, Osvaldo; Lee, Semin (June 2021, Journal of the American Chemical Society)

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