Access to Dienophilic Ene-Triketone Synthons by Oxidation of Diketones with an Oxoammonium Salt
摘要:
Here we describe the oxidation of 1,3-cyclohexanediones with 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate (Bobbitt's salt) to generate 5-ene-1,2,4-triones in moderate-to-good (40-80%) yields. This inexpensive oxidant facilitated an unprecedented cascade of oxidation and elimination to yield novel ene-triketones. The reactivity of these products was explored in the Diets-Alder reaction and provided moderate-to-good yields of cycloaddition products. The products described in this study represent unique, densely functionalized, and versatile building blocks for the synthesis of more complex molecules.
Diversity-oriented approach to spirocycles with indole moiety via Fischer indole cyclization, olefin metathesis and Suzuki–Miyaura cross-coupling reactions
作者:Sambasivarao Kotha、Rashid Ali、Venu Srinivas、Nimita G. Krishna
DOI:10.1016/j.tet.2014.11.024
日期:2015.1
A range of aryl substituted spirocycles containing the indole moiety have been assembled through Claisenrearrangement, Fischer indole cyclization, ring-closingmetathesis and the Suzuki–Miyauracross-coupling reactions. Some of these molecules contain either a spirocyclic system or an indeno[1,2-b]indole framework, which is present in diverse bioactive targets. Here, we have used simple and readily
通过克莱森重排,费歇尔吲哚环化,闭环易位和铃木-宫浦交叉偶联反应,已组装了一系列含有吲哚部分的芳基取代螺环。这些分子中的一些包含螺环系统或茚并[1,2- b ]吲哚骨架,它们存在于各种生物活性靶标中。在这里,我们使用了简单易用的起始材料来生成螺环化合物库,其中螺环化合物的结构具有吲哚单元。
Spiro-Annulation <i>via</i> Ring Closing Metathesis Reaction
作者:Sambasivarao Kotha、Ethirajan Manivannan、Thota Ganesh、Nampally Sreenivasachary、Ashoke Deb
DOI:10.1055/s-1999-2896
日期:——
Various spiro cyclic systems are prepared from β-di-carbonyl compounds and active methylene substrates via palladium catalyzed allylation and ring-closing metathesis (RCM) reaction as key steps.
An Unexpected Directing Effect in the Asymmetric Transfer Hydrogenation of α,α-Disubstituted Ketones
作者:Rina Soni、John-Michael Collinson、Guy C. Clarkson、Martin Wills
DOI:10.1021/ol201643v
日期:2011.8.19
alpha,alpha-Disubstituted ketones containing an aromatic ring or alkene are reduced in high enantiomeric excess using an asymmetric transfer hydrogenation catalyst. The sense of reduction indicates that the unsaturated region of the ketone adopts a position adjacent to the Ru-bound eta(6)-arene ring in the reduction transition state.
Development of a One-Pot Four C–C Bond-Forming Sequence Based on Palladium/Ruthenium Tandem Catalysis
A one-pot four C-C bond-forming sequence has been developed using two distinct transition metal complexes. The sequence entails a double Pd-catalyzed allylic alkylation followed by a Ru-catalyzed ring-closing metathesis and a Pd-catalyzed Heck coupling. The use of various active methylene nucleophiles was examined with yields up to 76% (93% per C-C bond).
Allylic Alkylation and Ring-Closing Metathesis in Sequence: A Successful Cohabitation of Pd and Ru
作者:Claire Kammerer、Guillaume Prestat、Thomas Gaillard、David Madec、Giovanni Poli
DOI:10.1021/ol702694v
日期:2008.2.1
An allylic alkylation/ring-closing metathesis domino catalytic process, wherein a palladium and a ruthenium catalyst are concomitantly present in the reaction mixture from the outset of the reaction, is developed. Evidence for Grubbs' catalysts activity in allylic alkylation is also reported.