Photomediated synthesis of β-alkylketones from cycloalkanes
摘要:
beta-Cycloalkyl ketones are prepared through a photomediated radical addition reaction onto enones starting from the corresponding alkanes (i.e., cyclopentane, -hexane, -heptane, -dodecane and adamantane). The alkyl radicals are generated via hydrogen abstraction by either an organic (benzophenone) or an inorganic (tetrabutyl ammonium decatungstate, TBADT) photomediator. Isolated yields vary in the range 30-80%. Benzophenone has to be considered as a reagent, since it is used in an equimolar amount with respect to enone and is completely consumed in the reaction. On the contrary, TBADT is shown to behave as a photocatalyst, which is active for at least 50 cycles. The potential of photomediated reactions for the generation of radicals from unusual precursors and the synthetic significance of this method are discussed. (c) 2006 Elsevier Ltd. All rights reserved.
Acridine Photocatalysis: Insights into the Mechanism and Development of a Dual-Catalytic Direct Decarboxylative Conjugate Addition
作者:Hang T. Dang、Graham C. Haug、Vu T. Nguyen、Ngan T. H. Vuong、Viet D. Nguyen、Hadi D. Arman、Oleg V. Larionov
DOI:10.1021/acscatal.0c03440
日期:2020.10.2
Conjugateaddition is one of the most synthetically useful carbon–carbon bond-forming reactions; however, reactive carbon nucleophiles are typically required to effect the addition. Radical conjugateaddition provides an avenue for replacing reactive nucleophiles with convenient radical precursors. Carboxylicacids can serve as simple and stable radical precursors by way of decarboxylation, but activation
Direct β-Alkylation of Ketones and Aldehydes via Pd-Catalyzed Redox Cascade
作者:Chengpeng Wang、Guangbin Dong
DOI:10.1021/jacs.8b03530
日期:2018.5.16
report a direct β-alkylation of ketones and aldehydes with simple alkyl bromides through a Pd-catalyzed redox-cascade strategy. The use of a Cu cocatalyst is important for improved efficiency. The reaction is redox-neutral, without the need for strong acids or bases. Both cyclic and acyclic ketones, as well as α-branched aldehydes, are suitable substrates for coupling with secondary and tertiary alkyl
Photomediated synthesis of β-alkylketones from cycloalkanes
作者:Daniele Dondi、Anna Maria Cardarelli、Maurizio Fagnoni、Angelo Albini
DOI:10.1016/j.tet.2006.03.028
日期:2006.6
beta-Cycloalkyl ketones are prepared through a photomediated radical addition reaction onto enones starting from the corresponding alkanes (i.e., cyclopentane, -hexane, -heptane, -dodecane and adamantane). The alkyl radicals are generated via hydrogen abstraction by either an organic (benzophenone) or an inorganic (tetrabutyl ammonium decatungstate, TBADT) photomediator. Isolated yields vary in the range 30-80%. Benzophenone has to be considered as a reagent, since it is used in an equimolar amount with respect to enone and is completely consumed in the reaction. On the contrary, TBADT is shown to behave as a photocatalyst, which is active for at least 50 cycles. The potential of photomediated reactions for the generation of radicals from unusual precursors and the synthetic significance of this method are discussed. (c) 2006 Elsevier Ltd. All rights reserved.