Cyclization of Cyanoethylated Ketones as a Route to 6-Substituted Indole Derivatives
作者:Jan Bergman、Birgitta Stensland
DOI:10.1002/jhet.2048
日期:2014.1
δ‐Cyanoketones are quickly cyclized with KOtBu to 3‐aminocyclohex‐2‐enone derivatives, which in turn will give substitutedindoles when treated with oxalyl chloride. Thus, 3‐amino‐6,6‐dimethylcyclohex‐2‐enone gave 3‐chloro‐6,6‐dimethyl‐2,5,6,7‐tetrahydroindole‐2,5‐dione, whose structure was corroborated by X‐ray crystallography, whereas the corresponding molecule without the blocking gem‐dimethyl groups
A diastereodivergentasymmetric Michael-alkylation reaction between 3-chloro-oxindoles and β,γ-unsaturated-α-ketoesters has been achieved using L-RaPr2/Sc(OTf)3 and L-PrPr2/Mg(OTf)2 metal complexes as catalysts. Both rel-(1R,2S,3R) and rel-(1S,2S,3R) chiral spiro cyclopropane oxindoles were constructed in good yields, diastereoselectivities and ee values. The diastereodivergent control may originate
Time-Economical Synthesis of Bis-Spiro Cyclopropanes via Cascade 1,6-Conjugate Addition/Dearomatization Reaction of <i>para</i>
-Quinone Methides with 3-Chlorooxindoles
A simple method involving DBN‐mediated spirocyclopropanation of para‐quinonemethides with 3‐chlorooxindoles is reported, providing a novel class of bis‐spiro compounds in short reaction times under mild conditions. Twenty‐four examples of the target compounds were obtained in up to 96 % yield.
Asymmetric synthesis of 3-spirocyclopropyl-2-oxindoles via intramolecular trapping of chiral aza-ortho-xylylene
作者:Xiaowei Dou、Weijun Yao、Bo Zhou、Yixin Lu
DOI:10.1039/c3cc45369c
日期:——
Chiral aza-ortho-xylylene intermediates were efficiently generated from 3-chloro-3-substituted oxindole precursors. The first intramoleculartrapping of chiral aza-ortho-xylylene intermediates led to a highly asymmetric synthesis of 3-spirocyclopropyl-2-oxindoles.
Construction of Spirocyclopropane-Linked Heterocycles Containing Both Pyrazolones and Oxindoles through Michael/Alkylation Cascade Reactions
作者:Jun-Hua Li、Ting-Fan Feng、Da-Ming Du
DOI:10.1021/acs.joc.5b01940
日期:2015.11.20
diastereoselective Michael/alkylation cascade reaction of arylidenepyrazolones with 3-chlorooxindoles catalyzed by DIPEA was developed. A variety of highly functionalized spiro-pyrazolone-cyclopropane-oxindoles were obtained in excellent yields (up to 99%) with good to excellent diastereoselectivities (up to >25:1 dr). Moreover, the squaramide-catalyzed asymmetric reactions of arylidenepyrazolones with