An enantioselective cobalt-catalyzed C(sp )-H alkenylation of thioamides with but-2-ynoate ester coupling partners employing thioamide directing groups is presented. The method is operationally simple and requires only mild reaction conditions, while providing alkenylated products as single regioisomers in excellent yields (up to 85 %) and high enantiomeric excess [up to 91 : 9 enantiomeric ratio (er), or up to >99 : 1 er after a single recrystallization]. Diverse downstream derivatizations of the products are demonstrated, delivering a range of enantioenriched constructs. Extensive computational studies using density functional theory provide insight into the detailed reaction mechanism, origin of enantiocontrol, and the unusual regioselectivity of the alkenylation reaction.
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http://dx.doi.org/10.1002/anie.202316021 | DOI Listing |
Chem Asian J
November 2024
Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, No. 100 Shiquan 1st Rd, Sanmin District, Kaohsiung City, 807, Taiwan.
We report a metal additive-free iodine-promoted one-step structural reorganization of ynamide-ynes and simultaneous stereoselective 1,2-diiodination of the migrated alkyne to form stereospecific tetrasubstituted alkenyl diiodo-tethered indoles (E-isomer). Molecular iodine is cost effective, user friendly, less toxic, commercially available, and easy to handle. The key features of the reaction include metal-and additive-free environment, selectivity, structural reorganization, mild reaction conditions, simple workup, and gram-scale synthesis.
View Article and Find Full Text PDFAcc Chem Res
November 2024
State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China.
Nat Catal
April 2024
Department of Chemistry, University of Zurich, Zurich, Switzerland.
Angew Chem Int Ed Engl
April 2024
Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany).
We report the triply selective and sequential diversification of a single C carbon carrying Cl, Bpin and GeEt for the modular and programmable construction of sp-rich molecules. Various functionalizations of C -Cl and C -BPin (e.g.
View Article and Find Full Text PDFChemistry
January 2024
Department of Chemistry, Indian Institute of Technology-Guwahati, Kamrup, Assam, 781039, India.
Catalytic activities of Mn(I) complexes derived from expensive MnBr(CO) salt have been explored in various dehydrogenative transformations. However, the reactivity and selectivity of inexpensive high spin Mn(II) complexes are uncommon. Herein, we have synthesized four new Mn(II) complexes and explored switchable alkenylation and alkylation of methyl heteroarenes employing a single Mn(II)catalyst.
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