Recent studies have demonstrated that amides can be used in nickel-catalyzed reactions that lead to cleavage of the amide C-N bond, with formation of a C-C or C-heteroatom bond. However, the general scope of these methodologies has been restricted to amides where the carbonyl is directly attached to an arene or heteroarene. We now report the nickel-catalyzed esterification of amides derived from aliphatic carboxylic acids. The transformation requires only a slight excess of the alcohol nucleophile and is tolerant of heterocycles, substrates with epimerizable stereocenters, and sterically congested coupling partners. Moreover, a series of amide competition experiments establish selectivity principles that will aid future synthetic design. These studies overcome a critical limitation of current Ni-catalyzed amide couplings and are expected to further stimulate the use of amides as synthetic building blocks in C-N bond cleavage processes.
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http://dx.doi.org/10.1002/anie.201607856 | DOI Listing |
ChemSusChem
July 2024
Fuzhou University, department of chemistry, Qishan Campus;, No.2, Xueyuan Road, University Town, 350116, FUZHOU, CHINA.
Aftobetin is a non-invasive diagnosis probe of Alzheimer's disease, that can bind with aggregated β-amyloid peptide in eye's lenses, used for early diagnosis of Alzheimer's disease in a rapid and painless mode. The reported synthesis of this probe fell short in the aspects of greenness and economy due to the involvement of toxic Chromium(IV) oxidant, noble palladium catalyst, elevated reaction temperature, the long reaction time as well as the cumbersome workup. Herein, a holistic optimization of the synthetic process was achieved via the employment of flow technology and heterogenous photocatalysis.
View Article and Find Full Text PDFRSC Adv
September 2022
Federal University of Rio Grande do Norte, Institute of Chemistry 59072-970 Natal RN Brazil
An operationally simple and highly selective method for the decarboxylation of fatty acids under remarkably mild conditions is described herein. The activation of the aliphatic carboxylic acids by esterification with -hydroxyphthalimide (NHPI) enabled efficient deoxygenation to synthesize -alkanes in up to 67% yield, employing inexpensive PMHS as a hydrogen source, NiCl·6HO, bipyridine, and zinc in THF. In contrast to the conventional thermo-catalytic approaches, this protocol does not require high temperature and high pressure of hydrogen gas to deoxygenate biomass-derived carboxylic acids, thus representing an attractive alternative for producing drop-in biofuels.
View Article and Find Full Text PDFMolecules
September 2022
The Institute for Advanced Studies (IAS), Wuhan University, Wuhan 430072, China.
Carbonyl-containing oxindoles are ubiquitous core structures present in many biologically active natural products and pharmaceutical molecules. Nickel-catalyzed reductive aryl-acylation of alkenes using aryl anhydrides or alkanoyl chlorides as acyl sources is developed, providing 3,3-disubstituted oxindoles bearing ketone functionality at the 3-position. Moreover, nickel-catalyzed reductive aryl-esterification of alkenes using chloroformate as ester sources is further developed, affording 3,3-disubstituted oxindoles bearing ester functionality at the 3-position.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
June 2021
State Key Laboratory of Phytochemistry and Plant Resources in West China, Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
(-)-Isoscopariusin A was isolated from the aerial parts of Isodon scoparius. Chemical synthesis and spectroscopic analysis established its structure as an unsymmetrical meroditerpenoid bearing a sterically congested 6/6/4 tricyclic carbon skeleton with seven continuous stereocenters. A gram-scale synthesis was achieved in 12 steps from commercially available (+)-sclareolide.
View Article and Find Full Text PDFAcc Chem Res
February 2021
Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.
Convergent syntheses are characterized by the coupling of two or more synthetic intermediates of similar complexity, often late in a pathway. At its limit, a fully convergent synthesis is achieved when commercial or otherwise readily available intermediates are coupled to form the final target in a single step. Of course, in all but exceptional circumstances this level of convergence is purely hypothetical; in practice, additional steps are typically required to progress from fragment coupling to the target.
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