نتایج جستجو برای: desymmetrization

تعداد نتایج: 310  

Journal: :Compounds 2021

Non-symmetrical chiral 4,4′-bipyridines have recently found interest in organocatalysis and medicinal chemistry. In this regard, the development of efficient methods for their synthesis is highly desirable. Herein, a series non-symmetrical atropisomeric polyhalogenated were prepared further functionalized by using cross-coupling reactions. The desymmetrization step based on N-oxidation one two ...

2015
Ming Yang Jian Li Ang Li

Clostrubin is a potent antibiotic against methicillin- and vancomycin-resistant bacteria that was isolated from a strictly anaerobic bacterium Clostridium beijerinckii in 2014. This polyphenol possesses a fully substituted arene moiety on its pentacyclic scaffold, which poses a considerable challenge for chemical synthesis. Here we report the first total synthesis of clostrubin in nine steps (t...

2015
Pratap S. Patil Ting-Jen Rachel Cheng Medel Manuel L. Zulueta Shih-Ting Yang Larry S. Lico Shang-Cheng Hung

Tuberculosis, aggravated by drug-resistant strains and HIV co-infection of the causative agent Mycobacterium tuberculosis, is a global problem that affects millions of people. With essential immunoregulatory roles, phosphatidylinositol mannosides are among the cell-envelope components critical to the pathogenesis and survival of M. tuberculosis inside its host. Here we report the first synthesi...

Journal: :Chemistry 2009
David C Ebner Jeffrey T Bagdanoff Eric M Ferreira Ryan M McFadden Daniel D Caspi Raissa M Trend Brian M Stoltz

The first palladium-catalyzed enantioselective oxidation of secondary alcohols has been developed, utilizing the readily available diamine (-)-sparteine as a chiral ligand and molecular oxygen as the stoichiometric oxidant. Mechanistic insights regarding the role of the base and hydrogen-bond donors have resulted in several improvements to the original system. Namely, addition of cesium carbona...

2014
Nikolin Oberleitner Thomas Bayer Patricia Schaaf Naseem Iqbal Florian Rudroff Marko D. Mihovilovic Christin Peters Jan Muschiol Maria Kadow Stefan Saß Uwe T. Bornscheuer

An artificial ‘minipathway’ starting with oxyfunctionalization of readily available limonene to carveol followed by oxidation to the corresponding α,β-unsaturated ketone via an alcohol dehydrogenase, an enoate reductase for the subsequent reduction of the double bond and concluded by a Baeyer-Villiger monooxygenase for the formation of the corresponding lactone is presented. This extension of t...

Journal: :Symmetry 2011
Renato Dalpozzo Giuseppe Bartoli Giorgio Bencivenni

The 1,4-conjugate addition of nucleophiles to α,β-unsaturated carbonyl compounds represents one fundamental bond-forming reaction in organic synthesis. The development of effective organocatalysts for the enantioselective conjugate addition of malonate, nitroalkane and other carbon and heteroatom nucleophiles to cycloenones constitutes an important research field and has been explored in recent...

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