Cyclization of Cyanoethylated Ketones as a Route to 6‐Substituted Indole Derivatives

Abstract

δ‐Cyanoketones are quickly cyclized with KOtBu to 3‐aminocyclohex‐2‐enone derivatives, which in turn will give substituted indoles 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, 3‐aminocyclohex‐2‐enone, gave via hydrogen shifts 6‐chloro‐3‐hydroxyoxindole.

6-Chloro-1-phenylindoline-2,3-dione: absolute structure, non-linear optical and charge-transport properties

“…The crystal structures of many isatin derivatives have been reported, among the analogues of the title compound are 6-bromo-1-butylindoline-2,3-dione (Ji et al, 2009), 1-ethyl-5iodoindoline-2,3-dione (Wang et al, 2014), 6-chloroindoline-2,3-dione (Golen & Manke, 2016), 1-benzyl-5-fluoroindoline-2,3-dione (Sharmila et al, 2015) and 1-phenylindoline-2,3dione (Shukla & Rajeswaran, 2011). The synthesis of the title compound was reported in 2014 (Bergman & Stensland, 2014). Recently, we prepared this compound by a different method, which involves the use of O 2 in air as oxidant.…”

Sterisch anspruchsvolle 2,6‐disubstituierte Aniline durch direkte C‐N‐Bindungsknüpfung an Iod(III)‐Zentren

“…Alternativ können sie an direkten C‐N‐Kupplungsreaktionen auch in Abwesenheit von Metallpromotoren beteiligt werden – ein Aspekt, der beachtliches Interesse auf biomedizinischem Gebiet geweckt hat. Derartige Beispiele beinhalten Anilin‐Synthesen durch Arylierung von Amiden,, aromatischen Aminen,, Methoxyaminen, Ammoniak und Heterocyclen, sowie radikalische Umlagerungen . Obwohl Synthesen von Anilinen bereits für eine große Bandbreite von Substraten und Produkten bekannt sind, bemerkten wir, dass für direkte C‐N‐Bindungsknüpfungen auf dem Gebiet von 2,6‐disubstituierten Anilinderivaten nur wenige Synthesevorschläge existieren .…”

Oxalyl Chloride: A Versatile Reagent in Organic Transformations

“…It has been used as a privileged C(O)CO source in the construction of a wide range of heterocyclic systems with five‐, six‐, seven‐ and eight‐membered rings; for instance, pyrrolediones, isatins, pyrroloisoquinolines, N ‐ω‐chloroalkylisatins, pyrrolopyrazinetriones, imidazolidine‐2,4,5‐trione nucleus, 2‐thioparabanic, furan‐2,3‐diones, thiophene‐2,3‐diones, and oxazolidinedione, as well as oxazolidinetrione . Several reactions have been reported in which oxalyl chloride employed as unexpected and fantastic sources for bond formations, e. g. C−C, OC−CO, C(O)CCl, C(O)C(Cl 2 )O, C(O)CCl 2 , CC(O)Cl, C‐C=O, and C(O)C−O . It can play important and crucial roles, not only as a synthon but also as a reagent in fundamental organic reactions.…”