α-Heteroarylation of Thioethers via Photoredox and Weak Brønsted Base Catalysis
作者:Edwin Alfonzo、Sudhir M. Hande
DOI:10.1021/acs.orglett.1c02151
日期:2021.8.6
thioethers to α-thio alkyl radicals and their addition to N-methoxyheteroarenium salts for the redox-neutral synthesis of α-heteroaromatic thioethers. Studies are consistent with a two-step activation mechanism, where oxidation of thioethers to sulfide radical cations by a photoredox catalyst is followed by α-C–H deprotonation by a weak Brønsted base catalyst to afford α-thio alkyl radicals. Further,
Photoredox and Weak Brønsted Base Dual Catalysis: Alkylation of α-Thio Alkyl Radicals
作者:Edwin Alfonzo、Sudhir M. Hande
DOI:10.1021/acscatal.0c03851
日期:2020.11.6
activation of thioethers to α-thio alkyl radicals and their addition to electron-deficient olefins to afford alkylated products through dual photoredox and weak Brønsted base catalysis. Mechanistic studies are consistent with a two-step activation mechanism, where oxidation of thioethers to their corresponding sulfide radical cations by an acridinium photoredox catalyst is followed with deprotonation by
Methods are disclosed for determining minute quantities of an analyte in a medium suspected of containing the analyte. One method comprises treating a medium suspected of containing an analyte under conditions such that the analyte, if present, causes a substrate having an oxidant cleavable linker and a photosenstizer to come into close proximity. The photosenstizer generates singlet oxygen which oxidatively cleaves the linker to form a product which can be detected in a sandwich detection assay such as LOCI. The amount of product detected is related to the amount of analyte in the medium. Compositions, kits, and compounds are also disclosed.
An efficient synthesis for the selective and efficient 1′-N derivatization of biotin is reported. The derivatized biotin acts as a stable analog of the carboxyphosphate intermediate in naturally-occurring biotin-mediated CO
2
transfer. The synthesis may readily be scaled up to perform large-scale, selective acylations of biotin. The stable analog of the intermediate can inhibit the activity of the biotin carboxylase enzymes such as acetyl CoA carboxylase, and HIV protease. The functionalization at the 1′-N of biotin results in the attachment of an electrophilic “handle” amenable to reaction with a wide variety of nucleophiles to generate a new family of biotin analogs.
报告了一种对生物素进行选择性和高效 1′-N 衍生化的高效合成方法。衍生后的生物素在天然生物素介导的 CO
2
转移。该合成方法可以很容易地放大,以进行大规模、选择性的生物素酰化。该中间体的稳定类似物可抑制生物素羧化酶(如乙酰 CoA 羧化酶)和 HIV 蛋白酶的活性。在生物素的 1′-N 处进行官能化后,会附着一个亲电 "柄",可与多种亲核物发生反应,生成一系列新的生物素类似物。