102-17-0Relevant articles and documents
Palladium-catalyzed carbonylation of benzylic ammonium salts to amides and esters: Via C-N bond activation
Yu, Weijie,Yang, Shuwu,Xiong, Fei,Fan, Tianxiang,Feng, Yan,Huang, Yuanyuan,Fu, Junkai,Wang, Tao
supporting information, p. 3099 - 3103 (2018/05/22)
An efficient palladium-catalyzed carbonylation reaction of readily available quaternary ammonium salts with CO is reported for the first time to afford arylacetamides and arylacetic acid esters via benzylic C-N bond cleavage. This protocol features mild reaction conditions under atmospheric pressure of CO, a redox-neutral process without an additional oxidant, and a broad substrate scope for various kinds of amines, alcohols and phenols.
A novel aromatic carbocation-based coupling reagent for esterification and amidation reactions
Nguyen, Thanh V.,Lyons, Demelza J.M.
supporting information, p. 3131 - 3134 (2015/06/17)
A novel tropylium-based coupling reagent has been developed to facilitate the synthesis of a series of esters, amides, lactones and peptides under mild reaction conditions. Remarkably, this reagent can be used in catalytic amounts in conjunction with a sacrificial reagent, offering a new and efficient method for nucleophilic coupling reactions of carboxylic acids.
Benzyloxy(4-substituted benzyloxy)carbenes. Generation from oxadiazolines and fragmentation to radical pairs in solution
Merkley,Warkentin
, p. 942 - 949 (2007/10/03)
Thermolysis of 2,2-dibenzyloxy-5,5-dimethyl-Δ3-1,3,4-oxadiazoline in benzene at 110°C leads to dibenzyloxycarbene. The carbene was trapped with tert-butyl alcohol to afford dibenzyl-tert-butyl orthoformate. In the absence of a trapping agent for the carbene, it fragmented to benzyloxycarbonyl and benzyl radicals, as shown by trapping the latter with TEMPO. In the absence of both TEMPO and tert-butyl alcohol, the radicals were partitioned between coupling to benzyl phenylacetate and decarboxylation, with subsequent formation of bibenzyl. The preferred sense of fragmentation of the analogous carbenes from benzyloxy-(p-substituted-benzyloxy)carbenes was determined by comparing the yields of the two possible esters, ArCH2O(CO)CH2Ph and PhCH2O(CO)CH2Ar. It was found that an electron-withdrawing group in the para position favoured fragmentation to the benzylic radical containing that group. A Hammett plot of the data gave a best fit with σ- substituent constants (r = 0.994, ρ((PhH, 110°C) = 0.7)) suggesting that the fragmentation involves charge separation in the sense that increases electron density on the group that is becoming a benzylic radical and decreases electron density on the carbonyl group that is becoming the benzyloxycarbonyl radical.
A convenient preparation of p-methoxybenzyl esters
Wang,Golding,Potter
, p. 4197 - 4204 (2007/10/03)
Carboxylic acids are conveniently and efficiently protected as their p-methoxybenzyl esters under very mild conditions using the pre-formed reagent N,N'-diisopropyl-O-(4-methoxybenzyl)isourea, and this method allows selective protection of carboxylic acids in the presence of other functionalities such as enolisable ketones and alcohol groups.
Synthesis of substituted benzyl esters
-
, (2008/06/13)
A process for preparing certain substituted benzyl esters of phenylacetic acids by esterification in a solvent in which the salt of the acid is insoluble, and in the presence of a phase transfer catalyst.
Photochemistry of α-Aryl Carboxylic Anhydrides. Part 4. Photoreactions of Some Asymmetrical Anhydrides derived from o- and p-Methoxyphenylacetic Acid, and of Some of the Phenylacetate Ester Photoproducts
Roof, Antonius A. M.,Woerden, Hendrik F. van,Cerfontain, Hans
, p. 838 - 841 (2007/10/02)
Irradiation of the two asymmetrical carboxylic anhydrides R1C6H4CH2.CO.O.CO.CH2C6H5 (1a and 1b) at 254 nm in acetonitrile leads to the formation of esters and bibenzyls.Among the esters produced, the asymmetrical ones with structure R1C6H4CH2.O(C=O)CH2C6H5 are the most abundant.These are for the greater part formed intramolecularly by decarbonylation of one excited anhydride molecule.This result is in line with a mechanism involving electron transfer after excitation of the anhydride molecule.The bibenzyls are formed by the recombination of benzyl radicals.In the initial stage of the reaction of the anhydrides, the three bibenzyls are formed with the asymmetrical one predominating .In the later stages, when substantial amounts of esters are present, the formation of the bibenzyls also originates in part from the photodecomposition of the esters.The photochemistry of the various (symmetrical and asymmetrical) esters which are photoproducts from the anhydrides (1a and b) has also been studied.The symmetrical esters (2a and b) afforded quantitatively the bibenzyls (3a and b), respectively.The asymmetrical esters gave variable yields of the three (possible) bibenzyls, depending on the type of ester considered.For the asymmetrical esters for which bibenzyl formation could be quenched by (Z)-piperylene, the three bibenzyls were formed in a close to statistical ratio, e.g. (2c) yielded the bibenzyls (3a, c, and e) in a ratio of 1:2.5:1.With the esters for which the photodecarboxylation was not quenchable by (Z)-piperylene, a relatively higher yield of the asymmetrical bibenzyl was found, e.g. (2d) yielded the bibenzyls (3b, d, and e) in a ratio of 1:6:1.These results are rationalized in terms of a recombination of free radicals resulting from the triplet excited esters after spin inversion in the former case, and a recombination of a radical pair in the solvent cage resulting from the singlet excited or shortlived triplet excited ester in the latter case.
