We introduce a highly efficient ligation system based on a visible light-induced rearrangement affording a thiophenol which rapidly undergoes thiol-Michael additions. Unlike conventional light-triggered thiol-ene/yne systems, which rely on the use of photocaged bases/nucleophiles, (organo)-photo catalysts, or radical photoinitiators, our system provides a light-induced reaction in the absence of any additives. The ligation is self-catalyzed the pyridine mediated deprotonation of the photochemically generated thiophenol. Subsequently, the thiol-Michael reaction between the thiophenol anion and electron deficient alkynes/alkenes proceeds additive-free. Hereby, the underlying photoinduced rearrangement of -thiopyrinidylbenzaldehyde (TPyB) generating the free thiol is described for the first time. We studied the influence of various reactions conditions as well as solvents and substrates. We exemplify our findings in a polymer end group modification and obtained macromolecules with excellent end group fidelity.
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http://dx.doi.org/10.1021/jacs.1c03213 | DOI Listing |
J Org Chem
May 2024
Key Laboratory for Northern Urban Agriculture of Ministry of Agriculture and Rural Affairs, Beijing University of Agriculture, 102206 Beijing, China.
A self-catalyzed, visible-light-induced, directly selective C3-H aroylation of quinoxalin-2(1)-ones via energy transfer and hydrogen atom transfer (HAT) catalysis has been developed. The method is highly atom-economical, eco-friendly, and easy to handle. Notably, the reaction proceeded efficiently with ambient air as the sole oxidant at room temperature.
View Article and Find Full Text PDFJ Org Chem
May 2024
College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
An efficient synthesis of functionalized 3-acyl-2-indazoles via visible-light-induced self-catalyzed energy transfer was developed. This method utilized a self-catalyzed energy transfer process between 2-indazoles and α-keto acids, offering advantages like absence of photosensitizers, metal catalysts, and strong oxidants, broad substrate compatibility, and operational simplicity under mild conditions.
View Article and Find Full Text PDFNanoscale Adv
March 2023
Research Center for Integrated Quantum Electronics, Hokkaido University Sapporo 060-0813 Japan
GaAs/AlGaAs core-shell nanowires, typically having 250 nm diameter and 6 μm length, were grown on 2-inch Si wafers by the single process of molecular beam epitaxy using constituent Ga-induced self-catalysed vapor-liquid-solid growth. The growth was carried out without specific pre-treatment such as film deposition, patterning, and etching. The outermost Al-rich AlGaAs shells form a native oxide surface protection layer, which provides efficient passivation with elongated carrier lifetime.
View Article and Find Full Text PDFChemistry
March 2023
Department of Pharmacy, University of Naples Federico II, via D. Montesano 49, 80131, Napoli, Italy.
Isocyanide-based multicomponent reactions claim a one century-old history of flourishing developments. On the other hand, the enormous impact of recent progresses in visible light photocatalysis has boosted the identification of new straightforward and green approaches to both new and known chemical entities. In this context, the application of visible light photocatalytic conditions to multicomponent processes has been promoting key stimulating advancements.
View Article and Find Full Text PDFJ Org Chem
December 2022
College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
Herein, a visible-light-triggered photocatalyst-free radical cascade Minisci reaction of heteroarenes, alkenes, and water/alcohols to obtain diverse β-C(sp) heteroarylated alcohols/ethers has been developed. Achieved under mild and simple conditions, this protocol is scalable and features broad substrate scope and functional group tolerance. Mechanistic studies demonstrate that the heteroarene can be served as a photocatalyst to engage single-electron transfer with persulfate.
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