A metal free and highly stereoselective procedure for the synthesis of 2,3-unsaturated-C-glycosides has been developed between glycals and unactivated aryl acetylenes in the presence of TMSOTf through a triflated C-vinyl glycosides intermediate. The flexibility of the procedure was tested by a wide variety of glycals and unactivated aryl acetylenes (20 examples). The corresponding alkynyl C-glycosides were obtained in good yields with completely α-selectivity in a short time (<25 min). And a plausible mechanism for the synthesis of alkynyl C-glycosides was depicted.
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http://dx.doi.org/10.1007/s10719-016-9718-7 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Zhejiang Uiversity, Chemistry, 866 Yuhangtang Road, 310058, Hangzhou, CHINA.
Heck silylation of unactivated alkenes is an efficient strategy for the synthesis of useful organosilicon compounds. However, extensive efforts have been dedicated to only achieving achiral molecules. Herein, a highly regio- and enantioselective cobalt-catalyzed Heck silylation of unactivated alkenes with hydrosilanes is reported for the first time, providing access to axially chiral alkenes in good to excellent yields with 87-98% ee.
View Article and Find Full Text PDFOrg Lett
January 2025
China Guangxi Key Laboratory of Pharmaceutical Precision Detection and Screening, Guangxi Key Laboratory of Bioactive Molecules Research and Evaluation, and Key Laboratory of Micro-Nanoscale Bioanalysis and Drug Screening of Guangxi Education Department, Pharmaceutical College, Guangxi Medical University, Nanning 530021, China.
Herein, a one-pot domino catalyzed three-component process is described, which is initiated by a palladium/zinc cooperatively catalyzed cycloaddition between trimethylenemethane (TMM) and unactivated alkyl/aryl imines, followed by one-pot isomerization and Zn(OTf)-catalyzed DDQ oxidation, furnishing valuable substituted pyrroles. We disclose that the palladium/zinc cooperative catalysis affords a dual-Zn(OTf)-stabilized azapalladacycle, wherein the Pd-N bond is polarized by Zn(OTf), facilitating a unique outer-sphere allylic amination. Moreover, subsequent DDQ dehydrogenation can be feasibly promoted by zinc catalysis.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
We report a Ni-catalyzed vicinal alkylarylation of unactivated alkenes in γ,δ- and δ,ε-alkenylamines with aryl halides and alkylzinc reagents. The reaction is enabled by amine coordination and can use all primary, secondary, and tertiary amines. The reaction constructs two new C(sp)-C(sp) and C(sp)-C(sp) bonds and produces δ- and ε-arylamines with C(sp)-branching at the γ- and δ-positions.
View Article and Find Full Text PDFJ Org Chem
January 2025
Institute of Materia Medica, School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing 211816, P. R. China.
In this study, we present a novel catalyst-free energy transfer mediated radical rearrangement strategy for the aryl-heterofunctionalization of unactivated alkynes, leading to the synthesis of polyfunctional olefins with exceptional stereoselectivity. This innovative approach, driven by visible light, exemplifies green chemistry principles by eliminating the reliance on transition metals, external oxidants, and photocatalysts. The broad applicability of our method is demonstrated through the successful synthesis of a diverse array of compounds, including vinyl sulfones, vinyl selenides, and vinyl sulfides.
View Article and Find Full Text PDFChemistry
December 2024
Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka, 565-0871, Japan.
Deuterated molecules are of growing interest because of the specific characteristics of deuterium, such as stronger C-D bonds being stronger than C-H bonds. Polyethylene glycols (PEGs) are widely utilized in scientific fields (e. g.
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