Copper(I)-Catalyzed Aerobic Oxidation of α-Diazoesters

Xu, Changming; Wang, Yongchang; Bai, Lei

doi:10.1021/acs.joc.0c01744

Cited by 20 publications

(4 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, this method required a large (10 equiv) excess of pyridine and was burdened by known carbene byproducts diazine 3 and 2,3-diphenylmaleate 4 . To avoid competitive side reactions and determine the photochemical dependency of the ylide rearrangement, we synthesized pyridinium bromide salt 5 (Scheme b) and irradiated it with blue light in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).…”

mentioning

confidence: 99%

Unified Synthesis of Azepines by Visible-Light-Mediated Dearomative Ring Expansion of Aromatic N-Ylides

et al. 2021

View full text Add to dashboard Cite

Herein, we report a unified approach to azepines by dearomative photochemical rearrangement of aromatic N-ylides. Deprotonation of quaternary aromatic salts with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or N,N,N′,N’-tetramethylquanidine (TMG) under visible light irradiation provides mono- and polycyclic azepines in yields up to 98%. This ring-expansion presents a new mode of access to functionalized azepines from N-heteroarenes using two straightforward steps and simple starting materials.

show abstract

mentioning

confidence: 99%

Unified Synthesis of Azepines by Visible-Light-Mediated Dearomative Ring Expansion of Aromatic N-Ylides

et al. 2021

View full text Add to dashboard Cite

show abstract

“…This pathway has been supported by a set of appropriately designed experiments as well as NMR analysis . Therefore, in addition to a new entry to benzils, our investigation has also offered a perspective for the capture of active ketenes with oxygenated metal ions, a research topic that has not yet been addressed in the literature up to date . To gain a better understanding of the protocol, its further extension to wider ranges of transition-metal catalysts and diazocarbonyl compounds is underway.…”

Section: Resultsmentioning

confidence: 99%

Rhodium-Catalyzed Aerobic Decomposition of 1,3-Diaryl-2-diazo-1,3-diketones: Mechanistic Investigation and Application to the Synthesis of Benzils

Zhu

Tsai

2020

J. Org. Chem.

View full text Add to dashboard Cite

The conversion of 1,3-diaryl-2-diazo-1,3-diketones to 1,2-daryl-1,2-diketones (benzils) is reported based on a rhodium(II)-catalyzed aerobic decomposition process. The reaction occurs at ambient temperatures and can be catalyzed by a few dirhodium carboxylates (5 mol %) under a balloon pressure of oxygen. Moreover, an oxygen atom from the O 2 reagent is shown to be incorporated into the product, and this is accompanied by the extrusion of a carbonyl unit from the starting materials. Mechanistically, it is proposed that the decomposition may proceed via the interaction of a ketene intermediate resulting from a Wolff rearrangement of the carbenoid, with a rhodium peroxide or peroxy radical species generated upon the activation of molecular oxygen. The proposed mechanism has been supported by the results from a set of controlled experiments. By using this newly developed strategy, a large array of benzil derivatives as well as 9,10-phenanthrenequinone were synthesized from the corresponding diazo substrates in varying yields. On the other hand, the method did not allow the generation of benzocyclobutene-1,2-dione from 2-diazo-1,3-indandione because of the difficulty of inducing the initial rearrangement.

show abstract

“…Later, Song et al utilized acetophenones, [7] whereas, Bai's group utilized α-diazo esters as substrates for the synthesis of α-keto esters. [8] Collectively, the requirement of metal catalysts, acids and bases, pre-synthesized, unstable, and shock-sensitive starting materials, high boiling solvents, and elevated reaction temperature impede the applicability of these methods. Visible-light photocatalysis has emerged as a powerful tool for the generation of radicals and thus might provide an alternative to achieve a wide spectrum of reactions including the title reaction in a step economical way without the need to use stoichiom etric amounts of reagents.…”

Section: Introductionmentioning

confidence: 99%

Esterification of Carboxylic Acids utilizing Eosin Y as a Photoacid Catalyst

Tripathi,

Gupta,

Sharma

2024

Preprint

View full text Add to dashboard Cite

Esters represent a vital functional group in organic chemistry and are prominently featured in valuable molecules. Traditional approaches for ester synthesis from acids typically entail the use of strong acids and toxic activating agents. Photoacid-catalyzed organic synthesis has recently come to the fore in several important transformations accruing the benefits of acid-based reactions under mild conditions. In this context, a green and sustainable method for esterification is proposed wherein, Eosin Y is introduced as a multifunctional photoacid catalyst that can be activated with visible light and catalyze the esterification of carboxylic acids. The present strategy is fairly broad and applies to the esterification of cinnamic acids, α-keto acids, and phenyl propiolic acids. The scope of carboxylic acids and alkyl alcohols includes several examples and therefore provides various carboxylic ester building blocks of pharmaceutical interest. Elaborated mechanistic studies revealed that proton-coupled electron transfer (PCET) between Eosin Y and carboxylic acid might facilitate the formation of a transient ketyl radical. This ketyl radical would subsequently undergo coupling with alkyl alcohols, yielding carboxylic esters in good to excellent yields.

show abstract

Copper(I)-Catalyzed Aerobic Oxidation of α-Diazoesters

Cited by 20 publications

References 49 publications

Unified Synthesis of Azepines by Visible-Light-Mediated Dearomative Ring Expansion of Aromatic N-Ylides

Unified Synthesis of Azepines by Visible-Light-Mediated Dearomative Ring Expansion of Aromatic N-Ylides

Rhodium-Catalyzed Aerobic Decomposition of 1,3-Diaryl-2-diazo-1,3-diketones: Mechanistic Investigation and Application to the Synthesis of Benzils

Esterification of Carboxylic Acids utilizing Eosin Y as a Photoacid Catalyst

Contact Info

Product

Resources

About