101723-19-7Relevant articles and documents
Photocatalytic Reductive C-O Bond Cleavage of Alkyl Aryl Ethers by Using Carbazole Catalysts with Cesium Carbonate
Yabuta, Tatsushi,Hayashi, Masahiko,Matsubara, Ryosuke
, p. 2545 - 2555 (2021)
Methods to activate the relatively stable ether C-O bonds and convert them to other functional groups are desirable. One-electron reduction of ethers is a potentially promising route to cleave the C-O bond. However, owing to the highly negative redox potential of alkyl aryl ethers (Ered -2.6 V vs SCE), this mode of ether C-O bond activation is challenging. Herein, we report the visible-light-induced photocatalytic cleavage of the alkyl aryl ether C-O bond using a carbazole-based organic photocatalyst (PC). Both benzylic and non-benzylic aryl ethers underwent C-O bond cleavage to form the corresponding phenol products. Addition of Cs2CO3 was beneficial, especially in reactions using a N-H carbazole PC. The reaction was proposed to occur via single-electron transfer (SET) from the excited-state carbazole to the substrate ether. Interaction of the N-H carbazole PC with Cs2CO3 via hydrogen bonding exists, which enables a deprotonation-assisted electron-transfer mechanism to operate. In addition, the Lewis acidic Cs cation interacts with the substrate alkyl aryl ether to activate it as an electron acceptor. The high reducing ability of the carbazole combined with the beneficial effects of Cs2CO3 made this otherwise formidable SET event possible.
A Unified and Practical Method for Carbon–Heteroatom Cross-Coupling using Nickel/Photo Dual Catalysis
Escobar, Randolph A.,Johannes, Jeffrey W.
supporting information, (2020/04/17)
While carbon–heteroatom cross-coupling reactions have been extensively studied, many methods are specific and limited to a particular set of substrates or functional groups. Reported here is a general method that allows for C?O, C?N and C?S cross-coupling reactions under one general set of conditions. We propose that an energy transfer pathway, in which an iridium photosensitizer produces an excited nickel(II) complex, is responsible for the key reductive elimination step that couples aryl bromides, iodides, and chlorides to 1° and 2° alcohols, amines, thiols, carbamates, and sulfonamides, and is amenable to scale up via a flow apparatus.
Simple and rapid p-methoxybenzylation of hydroxy and amide groups at room temperature by NaOt-Bu and DMSO
Hamada, Shohei,Sugimoto, Koichi,Iida, Masashi,Furuta, Takumi
supporting information, (2019/11/13)
The p-methoxybenzylation of hydroxy and amide groups by p-methoxybenzyl chloride utilizing NaOt-Bu in DMSO is described. p-Methoxybenzylation of sterically hindered menthol using NaOt-Bu in DMSO proceeded faster than the commonly used methods which use Na
Facile and selective deprotection of PMB ethers and esters using oxalyl chloride
Ilangovan, Andivelu,Anandhan, Karnambaram,Kaushik, Mahabir Prasad
supporting information, p. 1081 - 1084 (2015/02/19)
Oxalyl chloride, (0.5 equiv) was found to cleave the PMB group from alkyl, aryl PMB ethers, and esters to give corresponding alcohol and acid in good yields. This method offers simple and efficient protocol for the selective deprotection of PMB ether and ester in DCE at ambient temperature.
Benzylation of alcohols and phenols with N-(4-methoxybenzyl)-o- benzenedisulfonimide
Carlsen, Per H.J.
, p. 1799 - 1802 (2007/10/03)
N-(4-methoxybenzyl)-o-benzene disulfonimide was prepared from o- benzenedisulfonyl chloride and 4-methoxybenzylamine in dichloromethane. Reaction of this compound with alcohols or phenols undere basic conditions gave the corresponding 4-methoxybenzyl ethers in good yields. Primary alkylamines were converted to the corresponding alcohols by treating the benzenedisulfonimido derivative with aqueous KOH in DMF solution.
Lewis Acid-Catalyzed Deprotection of p-Methoxybenzyl Ether
Bouzide, Abderrahim,Sauvé, Gilles
, p. 1153 - 1154 (2007/10/03)
The p-methoxybenzyl protecting group was readily removed from alcohols and phenols using catalytic amounts of AlCl3 or SnCl2 · 2H2O in the presence of EtSH at room temperature. Under these mild conditions other protecting groups such as methyl and benzyl ethers, p-nitrobenzoyl esters, TBDPS ethers and isopropylidene acetal were unchanged.
