Chromium-catalyzed enantioselective Nozaki-Hiyama-Kishi (NHK) reaction represents one of the most powerful approaches for the formation of chiral carbon-heteroatom bond. However, the construction of sterically encumbered tetrasubstituted stereocenter through NHK reaction still posts a significant challenge. Herein, we disclose a cobalt-catalyzed aza-NHK reaction of ketimine with alkenyl halide to provide a convenient synthetic approach for the manufacture of enantioenriched tetrasubstituted α-vinylic amino acid. This protocol exhibits excellent functional group tolerance with excellent 99 % ee in most cases. Additionally, this asymmetric reductive method is also applicable to the aldimine to access the trisubstituted stereogenic centers.
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http://dx.doi.org/10.1002/anie.202316012 | DOI Listing |
J Org Chem
September 2024
Department of Chemistry, Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States.
We describe the convergent total syntheses of strasseriolides A and B, which are potent antimalarial agents recently isolated from an unnamed plant found in a remote region of New Zealand. Both natural products exhibited potent activity against malaria parasite, . The synthesis involved asymmetric syn-aldol, asymmetric alkylation, and asymmetric Johnson-Claisen rearrangement to set six of the seven chiral centers of strasseriolide B.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2024
State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China.
Chiral allylic alcohols are highly prized in synthetic chemistry due to their versatile reactivity stemming from both alkenyl and hydroxyl functionalities. While the Nozaki-Hiyama-Kishi (NHK) reaction is a widely used method for the synthesis of allylic alcohols, it suffers from drawbacks such as the use of toxic chromium salts, high amounts of metal reductants, and poor enantiocontrol. To address these limitations, we present a novel approach involving a metallaphotoredox-catalyzed asymmetric NHK reaction for the production of chiral allylic alcohols.
View Article and Find Full Text PDFOrg Biomol Chem
June 2024
Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India.
Naturally occurring sesquiterpenes having humulane frameworks are structurally intriguing and possess significant biological profiles. Asymmetric synthesis of the alashanoids B, C, E, and F and 2,9-humuladien-6-ol-8-one is achieved for the first time through a linear synthetic strategy. Intramolecular late-stage Nozaki-Hiyama-Kishi (NHK) coupling is employed to access the eleven-membered macrocyclic core present in the target molecules.
View Article and Find Full Text PDFJ Am Chem Soc
February 2024
Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States.
The first general enantioselective alkyl-Nozaki-Hiyama-Kishi (NHK) coupling reactions are disclosed herein by employing a Cr-electrocatalytic decarboxylative approach. Using easily accessible aliphatic carboxylic acids (via redox-active esters) as alkyl nucleophile synthons, in combination with aldehydes and enabling additives, chiral secondary alcohols are produced in a good yield with high enantioselectivity under mild reductive electrolysis. This reaction, which cannot be mimicked using stoichiometric metal or organic reductants, tolerates a broad range of functional groups and is successfully applied to dramatically simplify the synthesis of multiple medicinally relevant structures and natural products.
View Article and Find Full Text PDFOrg Lett
January 2024
School of Pharmaceutical Sciences, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing 100084, China.
Carolacton, a naturally occurring MTHFD1 inhibitor, exhibits potent inhibitory activity against various RNA viruses including SARS-CoV-2. Herein, we present a concise total synthesis of carolacton, featuring the Krische allylation, Marshall coupling, NHK coupling, and RCM reaction as key elements. Additionally, we have synthesized three simplified carolacton analogues, one of which, namely, 14-demethyl-carolacton, exhibited notable antiviral activity.
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