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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(2):610-614
Direct radical additions to terminal alkynes have been widely employed in organic synthesis, providing credible access to the anti‐Markovnikov products. Because of the Kharasch effect, regioselective control for the formation of Markovnikov products still remains a great challenge. Herein, we develop a transition‐metal‐free, visible light‐mediated radical addition of S‐nucleophiles to terminal alkynes, furnishing a wide array of α‐substituted vinyl sulfones with exclusive Markovnikov regioselectivity. Mechanistic investigations demonstrated that radical/radical cross‐coupling might be the key step in this transformation. This radical Markovnikov addition protocol also provides an opportunity to facilitate the synthesis of other valuable α‐substituted vinyl compounds. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(47):15332-15336
We report herein the use of a dual catalytic system comprising a Lewis base catalyst such as quinuclidin‐3‐ol or 4‐dimethylaminopyridine and a photoredox catalyst to generate carbon radicals from either boronic acids or esters. This system enabled a wide range of alkyl boronic esters and aryl or alkyl boronic acids to react with electron‐deficient olefins via radical addition to efficiently form C−C coupled products in a redox‐neutral fashion. The Lewis base catalyst was shown to form a redox‐active complex with either the boronic esters or the trimeric form of the boronic acids (boroxines) in solution. 相似文献
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Kui Wu Lushun Wang Sonivette Coln‐Rodríguez Gerd‐Uwe Flechsig Ting Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(6):1788-1792
The development of visible‐light‐mediated allylation of unactivated sp3 C?H bonds is reported. The remote allylation was directed by the amidyl radical, which was generated by photocatalytic fragmentation of a pre‐functionalized amide precursor. Both aromatic and aliphatic amide derivatives could successfully deliver the remote C?H allylation products in good yields. A variety of electron deficient allyl sulfone systems could be used as δ‐carbon radical acceptor. 相似文献
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Fei Ye Florian Berger Hao Jia Joseph Ford Alan Wortman Jonas Brgel Christophe Genicot Tobias Ritter 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(41):14757-14761
Incorporation of the CF3 group into arenes has found increasing importance in drug discovery. Herein, we report the first photoredox‐catalyzed cross‐coupling of aryl thianthrenium salts with a copper‐based trifluoromethyl reagent, which enables a site‐selective late‐stage trifluoromethylation of arenes. The reaction proceeds with broad functional group tolerance, even for complex small molecules on gram scale. The method was further extended to produce pentafluoroethylated derivatives. 相似文献
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Rick C. Betori Catherine M. May Karl A. Scheidt 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(46):16642-16646
Chemical transformations that install heteroatoms into C?H bonds are of significant interest because they streamline the construction of value‐added small molecules. Direct C?H oxyfunctionalization, or the one step conversion of a C?H bond to a C?O bond, could be a highly enabling transformation due to the prevalence of the resulting enantioenriched alcohols in pharmaceuticals and natural products,. Here we report a single‐flask photoredox/enzymatic process for direct C?H hydroxylation that proceeds with broad reactivity, chemoselectivity and enantioselectivity. This unified strategy advances general photoredox and enzymatic catalysis synergy and enables chemoenzymatic processes for powerful and selective oxidative transformations. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(3):746-750
A method for the decarboxylative macrocyclization of peptides bearing N‐terminal Michael acceptors has been developed. This synthetic method enables the efficient synthesis of cyclic peptides containing γ‐amino acids and is tolerant of functionalities present in both natural and non‐proteinogenic amino acids. Linear precursors ranging from 3 to 15 amino acids cyclize effectively under this photoredox method. To demonstrate the preparative utility of this method in the context of bioactive molecules, we synthesized COR‐005, a somatostatin analogue that is currently in clinical trials. 相似文献