N-Sulfonyl 1,2,3-triazoles readily form rhodium(II) azavinyl carbenes, which react with olefins to produce cyclopropanes with excellent diastereo- and enantioselectivity and in high yield.
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http://dx.doi.org/10.1021/ja908075u | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
A concise and convergent synthesis of the isosteroidal alkaloids veratramine and 20--veratramine has been accomplished. A Horner-Wadsworth-Emmons olefination joins two chiral building blocks of approximately equal complexity and a transition-metal catalyzed intramolecular Diels-Alder cycloaddition-aromatization cascade constructs the tetrasubstituted arene. Other key steps include a highly diastereoselective crotylation of an -sulfonyl iminium ion and an Eschenmoser fragmentation.
View Article and Find Full Text PDFChem Rev
January 2025
Department of Chemistry, Northeast Normal University, Changchun 130024, China.
-Sulfonyl hydrazones have been extensively used as operationally safe carbene precursors in modern organic synthesis due to their ready availability, facile functionalization, and environmental benignity. Over the past two decades, there has been tremendous progress in the carbene chemistry of -sulfonyl hydrazones in the presence of transition metal catalysts, under metal-free conditions, or using photocatalysts under photoirradiation conditions. Many carbene transfer reactions of -sulfonyl hydrazones are unique and cannot be achieved by any alternative methods.
View Article and Find Full Text PDFOrg Lett
January 2025
Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, China.
We herein report a photochemical Truce-Smiles rearrangement reaction of -sulfinyl acrylamides with bromodifluoroacetamides resulting in the synthesis of a series of aryl difluoroglutaramides in moderate to good yields. The asymmetric synthesis using chiral sulfinamides produced quaternary carboncentered glutaramide products with a modest enantioselectivity. This protocol effectively complements previous Truce-Smiles rearrangement methods involving -sulfonyl acrylamides.
View Article and Find Full Text PDFACS Omega
December 2024
School of Chemistry & Physics, University of KwaZulu-Natal, Durban 4000, South Africa.
We report a state-of-the-art synthesis and isolation procedure for 13 Lewis base iminium salts (LBI) of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), confirming their structures meticulously by different spectral data.
View Article and Find Full Text PDFJ Org Chem
December 2024
Green Pharmaceutical Technology Key Laboratory of Luzhou City, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan 646000, P. R. China.
A cerium-catalyzed C-H alkylation of -sulfonyl ketimines with low-cost and readily available alkanes as alkyl sources was developed. This transformation proceeded through the synergy of photoinitiated ligand-to-metal charge transfer (LMCT) using a chlorine radical as an HAT reagent and air as a green oxidant. A series of alkylated -sulfonyl ketimines were synthesized with moderate to good yields in a highly atom-economic manner under chemical oxidant-free conditions.
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