459-64-3Relevant articles and documents
Mono- and Ditopic Bisfunctionalization of Graphene
Knirsch, Kathrin C.,Sch?fer, Ricarda A.,Hauke, Frank,Hirsch, Andreas
, p. 5861 - 5864 (2016)
For the first time, the bisfunctionalization of graphene by employing two successive reduction and covalent bond forming steps is reported. Bulk functionalization in dispersion and functionalization of individual sheets deposited on surfaces have both been carried out. Whereas in the former case attacks from both sides of the basal plane are possible and can lead to strain-free architectures, in the latter case, retrofunctionalizations can become important when the corresponding anion of the addend is a sufficiently good leaving group.
Aryl Radical Activation of C-O Bonds: Copper-Catalyzed Deoxygenative Difluoromethylation of Alcohols
Cai, Aijie,Liu, Wei,Yan, Wenhao
supporting information, p. 9952 - 9960 (2021/07/21)
Given their ubiquity in natural products and pharmaceuticals, alcohols represent one of the most attractive starting materials for the construction of C-C bonds. We report herein the first catalytic strategy to harness the reactivity of aryl radicals for the activation of C-O bonds in alcohol-derived xanthate esters, allowing for the discovery of the first catalytic deoxygenative difluoromethylation reaction. Under copper-catalyzed conditions, a wide variety of alkyl xanthate esters, readily synthesized from alcohol feedstocks, were activated by catalytically generated aryl radicals and were converted to the alkyl-difluoromethane products via alkyl radical intermediates. This scalable protocol exhibits a broad substrate scope and functional group tolerance, enabling late-stage modification of complex pharmaceutical agents. A one-pot protocol has been developed that allows for the direct use of free alcohols without purification of the xanthate esters. Mechanistic studies are consistent with the hypothesis of aryl radicals being formed and initiating the cleavage of the C-O bonds of xanthate esters, to generate alkyl radicals as the key intermediates. This aryl radical activation approach represents a new strategy for the activation of alcohols as cross-coupling partners.
Aryl Diazonium Salts: Powerful Arylating Agents for Catellani-Typeortho-Arylation
Fu, Ying,Guo, Liang-Liang,Zhang, Yu-Xia
supporting information, p. 17437 - 17444 (2021/12/02)
The Catellani reaction provides an efficient synthetic approach to polyfunctionalized arenes. However, the selectiveortho-arylating reagents employed in these reactions have been strictly limited to activated bromoarenes. As demonstrated in this work, aryl diazonium salts bearing both electron-donating and electron-withdrawing substituents, after in situ transformations with KI into the corresponding iodoarenes, were efficient arylating reagents for Catellani typeortho-arylation approaches.
Chemical and Genetic Studies on the Formation of Pyrrolones During the Biosynthesis of Cytochalasans
Zhang, Haili,Hantke, Verena,Bruhnke, Pia,Skellam, Elizabeth J.,Cox, Russell J.
supporting information, p. 3106 - 3113 (2021/01/20)
A key step during the biosynthesis of cytochalasans is a proposed Knoevenagel condensation to form the pyrrolone core, enabling the subsequent 4+2 cycloaddition reaction that results in the characteristic octahydroisoindolone motif of all cytochalasans. In this work, we investigate the role of the highly conserved α,β-hydrolase enzymes PyiE and ORFZ during the biosynthesis of pyrichalasin H and the ACE1 metabolite, respectively, using gene knockout and complementation techniques. Using synthetic aldehyde models we demonstrate that the Knoevenagel condensation proceeds spontaneously but results in the 1,3-dihydro-2H-pyrrol-2-one tautomer, rather than the required 1,5-dihydro-2H-pyrrol-2-one tautomer. Taken together our results suggest that the α,β-hydrolase enzymes are essential for first ring cyclisation, but the precise nature of the intermediates remains to be determined.
