The first cobalt-catalyzed cyanation, halogenation, and allylation via C-H activation have been realized. These formal SN-type reactions generate valuable (hetero)aryl/alkenyl nitriles, iodides, and bromides as well as allylated indoles using a bench-stable Co(III) catalyst. High regio- and mono-selectivity were achieved for these reactions. Additionally, allylation proceeded efficiently with a turnover number of 2200 at room temperature, which is unprecedented for this Co(III) catalyst. Alkenyl substrates and amides have been successfully utilized in Cp*Co(III)-catalyzed C-H activation for the first time.
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Org Biomol Chem
June 2019
Departamento de Química Orgánica e Inorgánica, Facultad de Ciencias-UEX, IACYS-Unidad de Química Verde y Desarrollo Sostenible, E-06006 Badajoz, Spain.
A fundamental question in origin-of-life studies and astrochemistry concerns the actual processes that initiate the formation of reactive monomers and their oligomerization. Answers lie partly in the accurate description of reaction mechanisms compatible with environments plausible on early Earth as well as cosmological scenarios in planetary factories. Here we show in detail that reactions of urea-as archetypal prebiotic substance-and reactive carbonyls-exemplified by glyoxal-lead to a vast repertoire of oligomers, in which different five- and six-membered non-aromatic heterocycles self-assemble and insert into chains or dendritic-like structures with masses up to 1000 Da.
View Article and Find Full Text PDFDig Dis Sci
February 2017
Department of Hepatopancreatobiliary Surgery, Drum Tower Hospital, Medical School of Nanjing University, Zhongshan Road 321, Nanjing, 210008, Jiangsu Province, China.
Background: Gene data on infiltrative hepatocellular carcinoma (iHCC) are still unknown.
Aims: This study aims to identify the gene expression signature of iHCC compared with single nodular (SN)-type HCC according to the gross classification.
Methods: The whole-exome sequencing was performed in six matched HCC tumor/normal pairs (three infiltrative type and three single nodular type) from six patients who received curative hepatectomy.
J Am Chem Soc
August 2016
Institut für Organische Chemie, Universität Regensburg, D-93053 Regensburg, Germany.
Catalysis with remote-stereocontrol provides special challenges in design and comprehension. One famous example is the dienamine catalysis, for which high ee values are reported despite insufficient shielding of the second double bond. Especially for dienamines with variable Z/E-ratios of the second double bond, no correlations to the ee values are found.
View Article and Find Full Text PDFJ Org Chem
June 2016
School of Pharmacy, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
The rhodium(III)-catalyzed γ-trifluoromethylallylation of various heterocyclic C-H bonds with CF3-substituted allylic carbonates is described. These reactions provide direct access to linear CF3-containing allyl frameworks with complete trans-selectivity via C-H bond activation followed by a formal SN-type reaction pathway.
View Article and Find Full Text PDFJ Am Chem Soc
December 2014
Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149 Münster, Germany.
The first cobalt-catalyzed cyanation, halogenation, and allylation via C-H activation have been realized. These formal SN-type reactions generate valuable (hetero)aryl/alkenyl nitriles, iodides, and bromides as well as allylated indoles using a bench-stable Co(III) catalyst. High regio- and mono-selectivity were achieved for these reactions.
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