A copper-catalyzedoxidative cleavage reaction of alkynes using NFSI and TBHP was described. Various terminal and internal alkyne substrates were employed to render quick access to aryl ketone products in moderate to good yields. NFSI not only functioned as N-centered radical precursors but also engaged in the aryl group migration. Mechanistic studies also suggested the important role of water in the
Palladium-Catalyzed Reductive Coupling of Acid Chlorides with .beta.-Stannyl Enones: Synthesis of 1,4-Diketones and Mechanistic Aspects
作者:Antonio M. Echavarren、Marta Perez、Ana M. Castano、Juan M. Cuerva
DOI:10.1021/jo00094a032
日期:1994.7
The palladium-catalyzed coupling of acid chlorides with (E)-1,2-bis(tri-n-butylstannyl)ethene or beta-stannyl enones gives butane-1,4-diones directly by reduction of the intermediate enedicarbonyl intermediate. The double bond conjugated with a single carbonyl group was not significantly reduced. The generality of the method is illustrated by two syntheses of the 1,4-diketone ipomeanine. By performing the reaction at lower temperatures, alpha,beta-unsaturated 1,4-diketones can also be prepared. The reduction of the intermediate alpha,beta-unsaturated 1,4-diketones probably proceeds by insertion of a palladium hydride, formed in situ by reaction of a Pd(II) complex with Bu(3)SnCl, followed by hydrolysis of the intermediate palladium enolate.
A simple synthetic protocol for oxidation of alkyl-arenes into ketones using a combination of HBr–H2O2
作者:Abu T. Khan、Tasneem Parvin、Lokman H. Choudhury、Subrata Ghosh
DOI:10.1016/j.tetlet.2007.01.172
日期:2007.3
A wide variety of alkyl- and cycloalkyl-arenes undergo benzylic C-H oxidation by employing a combination of 48% hydrogen bromide and 30% hydrogen peroxide in dichloromethane at room temperature. In addition, a chemoselective oxidation at the benzylic position is feasible by deactivating the aromatic ring using the same combination. (c) 2007 Elsevier Ltd. All rights reserved.
Ishido,Y. et al., Journal of the Chemical Society. Perkin transactions I, 1977, p. 521 - 530
作者:Ishido,Y. et al.
DOI:——
日期:——
Direct oxidative installation of nitrooxy group at benzylic positions and its transformation into various functionalities
作者:Shin Kamijo、Yuuki Amaoka、Masayuki Inoue
DOI:10.1016/j.tetlet.2011.06.118
日期:2011.9
C-H Nitrooxylation at benzylic positions has been achieved by employing the N-hydroxyphthalimide (NHPI) catalyst/cerium(IV) ammonium nitrate (CAN) reagent system. The nitrooxy groups were demonstrated to function as tentative hydroxy protecting groups, as well as excellent leaving groups for N- and C-substitution reactions. Hence, the present method offers a unique way to synthesize diverse O-. N-, or C-functionalized benzylic compounds from simple alkyl aromatics. (C) 2011 Elsevier Ltd. All rights reserved.