Free-Radical Addition of Heteroarenethiols and Heteroarylmethanethiols to Hexyne and Phenylacetylene. Chemical Behavior of the Transient .beta.-Sulfanylvinyl Radicals
摘要:
The free-radical reaction of a number of heteroarenethiols (including 2-thiophene-, 2-benzo[b]furan-and 2-benzo[b]thiophenethiol) and heteroarylmethanethiols (including 2-furyl-, 2-thienyl-, and 3-thienylmethanethiol) with hex-1-yne and phenylacetylene has been investigated in benzene solution both at 100 degrees C in the presence of AIBN and at room temperature in the presence of BEt(3)/O-2. Under both of these conditions the above thiols generally furnished transient 2-sulfanylvinyl radicals through regioselective addition of corresponding sulfanyl radicals to the terminal alkyne carbon, but 2-benzo[b]furanthiol failed to react with either alkyne in the presence of BEt(3)/O-2 and unexpectedely gave 2-(ethylsulfanyl)benzo[b]furan to a significant extent. The produced 2-(2-heteroarylsulfanyl) vinyl radicals largely preferred to undergo intermolecular H-abstraction reaction rather than intramolecular 5-endo cyclization onto the heteroaryl moiety of the 2-sulfanyl substituent. The 2-[(2-thienylmethyl)sulfanyl]- and, especially, 2-[(2-furylmethyl)sulfanyl]vinyl radicals, besides H-abstraction, promptly underwent intramolecular B-exo cyclization to give spiro radicals that interestingly underwent beta-scission of their respective C-S and C-O bond resulting in ring cleavage of the original heteroaryl group. The 2-[(3-thienylmethyl)sulfanyl]vinyl radicals did not exhibit any similar B-exo cyclization, but did undergo a 6-endo cyclization to a very slight extent.
An Organodiselenide with Dual Mimic Function of Sulfhydryl Oxidases and Glutathione Peroxidases: Aerial Oxidation of Organothiols to Organodisulfides
作者:Vandana Rathore、Aditya Upadhyay、Sangit Kumar
DOI:10.1021/acs.orglett.8b02756
日期:2018.10.5
peroxidase (GPx) enzymes for oxidation of thiols by oxygen and hydrogenperoxide, respectively, into disulfides has been presented. The developed catalyst oxidizes an array of organothiols into respective disulfides in practical yields by using aerial O2 to avoid any reagents/additives, base, and light source. The synthesized diselenide also catalyzes the reduction of hydrogenperoxide into water by following
A copper-catalyzed direct C–H chalcogenation of N-aryl-azaindoles with disulfides is described.
一种铜催化的直接C-H硫砜化反应,用于N-芳基-氮杂吲哚与二硫化物的反应。
Sequential C–H activation enabled expedient delivery of polyfunctional arenes
作者:Wensen Ouyang、Xiaoqing Cai、Xiaojian Chen、Jie Wang、Jianhang Rao、Yang Gao、Yanping Huo、Qian Chen、Xianwei Li
DOI:10.1039/d1cc03243g
日期:——
Modularconstruction of polyfunctional arenes from abundant feedstocks stands as an unremitting pursue in synthetic chemistry, accelerating the discovery of drugs and materials. Herein, using the multiple C–H activation strategy with versatile imidate esters, the expedient delivery of molecular libraries of densely functionalized sulfur-containing arenes was achieved, which enabled the concise construction
bond activation of tertiary amines and subsequent aryl thiolation has been explored. A variety of disulfides and series of tertiary amines were efficiently converted into the corresponding α,α-bis(arylthio) aldehydes in moderate to good yields. The reaction proceeded well under transition-metal-free conditions via a C–N activation process.