Chemoselective Oxidative C(CO)C(methyl) Bond Cleavage of Methyl Ketones to Aldehydes Catalyzed by CuI with Molecular Oxygen

Abstract

Bis zum Aldehyd: Eine kupferkatalysierte Umsetzung von Methylketonen zu Aldehyden wurde entwickelt. Die Methode kann für eine Vielzahl aromatischer und aliphatischer Methylketone verwendet werden und führt chemoselektiv zu Aldehyden, wobei lediglich Wasserstoff (H2) und Kohlendioxid (CO2) als Beiprodukte entstehen.

Copper catalyzed oxygen assisted C(CNOH)–C(alkyl) bond cleavage: a facile conversion of aryl/aralkyl/vinyl ketones to aromatic acids

“…Copper (II) acetate gave mixture of products (entry 7) and, with Copper Oxide only starting material was recovered (entry 8). In agreement with the earlier reports, 8 DMSO was found to be the appropriate solvent and no product formation was observed in solvents such as DMF, DCE and EtOH. Effectiveness of DMSO in aerobic oxidations may be attributed to its efficient metal-coordinating and catalyst stabilizing properties.…”

“…Interestingly, this led to the formation of 3a through oxidative scission of both the methyl and the methylene groups on either side of keto group, with an ending of oxidation process at the aromatic terminal (table 4). Recently, Bi et al 8 and Jiao et al 5 also observed a similar cleavage process during the conversion of aralkyl methyl ketones to aromatic aldehydes and aromatic esters respectively. Noteworthy is that this is in contrast to the productivity of haloform pathway where the similar substrate undergoes the oxidation of only methyl group to afford aralkyl acids.…”

“…Based on the recent publications on the oxidative C-C bond cleavage of acetophenones, [5][6][7][8] and inspired by a report by Chiba et al for the cleavage of α-keto imino copper intermediates 12 we aimed for the C-C bond cleavage that is adjacent to oxime. This may lead to the formation of corresponding nitriles.…”

“…This indicate the requirement of more than one equivalent of hydroxyl amine in the reaction. Since Bi et al 8 have reported the formation of glyoxal intermediate from the acetophenone under the same reaction conditions, we have employed glyoxal 9 to verify its formation. Interestingly, 9 was smoothly transformed to the corresponding acid 3a in 87% yield (scheme 3C) suggesting the possible formation of α-oxo intermediates.…”

Chemoselective Copper‐Catalyzed Acylation of Benzothiazoles with Aryl Methyl Ketones

“…[2] Very recently we developed an efficient method to prepare 2-arylbenzothiazoles from phenylacetic acids and a-hydroxyphenylacetic acids with benzothiazoles under aerobic copper-catalyzed oxidation conditions. [4] As part of our continuing interest in prepare 2-arylbenzothiazoles, we speculated that 2-arylbenzothiazoles could be formed from aryl methyl ketones and benzothiazoles in the presence of CuI and O 2 based on our previous research and the above literature report. [4] As part of our continuing interest in prepare 2-arylbenzothiazoles, we speculated that 2-arylbenzothiazoles could be formed from aryl methyl ketones and benzothiazoles in the presence of CuI and O 2 based on our previous research and the above literature report.…”