108062-64-2Relevant articles and documents
Photoinduced C—C Bond Cleavage and Oxidation of Cycloketoxime Esters
Zhao, Binlin,Tan, Hui,Chen, Cheng,Jiao, Ning,Shi, Zhuangzhi
, p. 995 - 999 (2018)
A novel structural reorganization of cycloketoxime esters beyond the traditional Beckmann rearrangement process has been established to build cyano-containing ketones in the presence of photocatalyst. This novel transformation is remarkable with selective C—C bond cleavage and an oxidation process enabled by DMSO used as the solvent, oxidant, and oxygen source avoiding acid, base and toxic cyanide salts as the cyano source. Further applications in late-stage modification of complex and chiral molecules have also been reported.
Synthesis of α-Arylated Cycloalkanones from Congested Trisubstituted Spiro-epoxides: Application of the House-Meinwald Rearrangement for Ring Expansion
Jeedimalla, Nagalakshmi,Jacquet, Camille,Bahneva, Diana,Youte Tendoung, Jean-Jacques,Roche, Stéphane P.
, p. 12357 - 12373 (2018/09/06)
A three-step sequence for the synthesis of α-arylated cyclohexanones and the most challenging cycloheptanones is reported. First, an efficient one-pot synthesis of β,β'-disubstituted benzylidene cycloalkanes (styrenes) using the palladium-catalyzed Barluenga reaction from readily available feedstock chemicals is described. Furthermore, an epoxidation followed by the House-Meinwald rearrangement (HMR) of spiro-epoxides is reported to produce a number of α-arylated cycloalkanones upon ring expansion. Reactions catalyzed by bismuth triflate underwent quasi-exclusively ring expansion for all substrates (electronically poor and rich), with yields ranging from 15% to 95%, thus demonstrating the difficulty of achieving ring enlargement for electron-deficient spiro-epoxides. On the other hand, by means of catalysis with aluminum trichloride, the rearrangement of spiro-epoxides proceeded typically in high yields and with remarkable regioselectivity on a broader substrate scope. In this case, a switch of regioselectivity was achieved for spiro-epoxides with electron-withdrawing substituents which enable the method to be successfully extended to some chemospecific arene shifts and the synthesis of aldehydes bearing a α-quaternary carbon. While the HMR has been extensively studied for smaller ring enlargement, we are pleased to report herein that larger cyclohexanones and cycloheptanones can be obtained efficiently from more sterically demanding trisubstituted spiro-epoxides bearing electron-releasing and electron-neutral arene substituents.
General and efficient insertions of carbons carrying aryl and heteroaryl groups: Synthesis of α-Aryl- And α-heteroaryl-substituted ketones
Katritzky, Alan R.,Toader, Dorin,Xie, Linghong
, p. 7571 - 7577 (2007/10/03)
Anions formed from the lithiation of a variety of 1-(arylmethyl)- and 1-(heteroarylmethyl)-benzotriazoles 1 with n-BuLi underwent addition to aliphatic and aromatic aldehydes and cyclic and acyclic ketones. Subsequent in situ thermal rearrangements of the intermediates in the presence of zinc bromide provided one-carbon chain-extended or ring-expanded α-aryl- and α-heteroaryl-substituted ketones 2 in moderate to excellent yields in simple one-pot operations with excellent regioselectivity in most cases. Substituent effects on the relative migration rates were investigated in the insertion reactions of 1-(4-methoxybenzyl)benzotriazole (1e) with XC6H4-COPh. The small and negative Hammett ρ+ value (-0.92) suggested that the rearrangements proceed via early, reagent-like, electron deficient transition states.
