1721-91-1Relevant academic research and scientific papers
Carbon Atom Insertion into Pyrroles and Indoles Promoted by Chlorodiazirines
Dherange, Balu D.,Kelly, Patrick Q.,Levin, Mark D.,Liles, Jordan P.,Sigman, Matthew S.
supporting information, p. 11337 - 11344 (2021/08/16)
Herein, we report a reaction that selectively generates 3-arylpyridine and quinoline motifs by inserting aryl carbynyl cation equivalents into pyrrole and indole cores, respectively. By employing α-chlorodiazirines as thermal precursors to the corresponding chlorocarbenes, the traditional haloform-based protocol central to the parent Ciamician-Dennstedt rearrangement can be modified to directly afford 3-(hetero)arylpyridines and quinolines. Chlorodiazirines are conveniently prepared in a single step by oxidation of commercially available amidinium salts. Selectivity as a function of pyrrole substitution pattern was examined, and a predictive model based on steric effects is put forward, with DFT calculations supporting a selectivity-determining cyclopropanation step. Computations surprisingly indicate that the stereochemistry of cyclopropanation is of little consequence to the subsequent electrocyclic ring opening that forges the pyridine core, due to a compensatory homoaromatic stabilization that counterbalances orbital-controlled torquoselectivity effects. The utility of this skeletal transform is further demonstrated through the preparation of quinolinophanes and the skeletal editing of pharmaceutically relevant pyrroles.
Highly Diastereo- And Enantioselective Ir-Catalyzed Hydrogenation of 2,3-Disubstituted Quinolines with Structurally Fine-Tuned Phosphine-Phosphoramidite Ligands
Hu, Xin-Hu,Hu, Xiang-Ping
supporting information, p. 10003 - 10006 (2019/12/24)
A highly diastereo- and enantioselective Ir-catalyzed hydrogenation of unfunctionalized 2,3-disubstituted quinolines, especially 3-alkyl-2-arylquinolines, has been realized. The success of this hydrogenation is ascribed to the use of a structurally fine-tuned chiral phosphine-phosphoramidite ligand with a (Sa)-3,3′-dimethyl H8-naphthyl moiety and (Rc)-1-phenylethylamine backbone. The hydrogenation displayed broad functional group tolerance, thus furnishing a wide range of optically active 2,3-disubstituted tetrahydroquinolines in up to 96% ee and with perfect cis-diastereoselectivity.
Metal- and Protection-Free [4 + 2] Cycloadditions of Alkynes with Azadienes: Assembly of Functionalized Quinolines
Saunthwal, Rakesh K.,Patel, Monika,Verma, Akhilesh K.
supporting information, p. 2200 - 2203 (2016/06/01)
A base promoted, protection-free, and regioselective synthesis of highly functionalized quinolines via [4 + 2] cycloaddition of azadienes (generated in situ from o-aminobenzyl alcohol) with internal alkynes has been discovered. The reaction tolerates a wide variety of functional groups which has been successfully extended with diynes, (2-aminopyridin-3-yl)methanol, and 1,4-bis(phenylethynyl)benzene to afford (Z)-phenyl-2-styrylquinolines, phenylnaphthyridine, and alkyne-substituted quinolines, respectively. The proposed mechanism and significant role of the solvent were well supported by isolating the azadiene intermediate and deuterium-labeling studies.
Pyrrolo[1,2-a]quinoxalines: Novel synthesis via annulation of 2-alkylquinoxalines
Ammermann, Sven,Hrib, Christian,Jones, Peter G.,Du Mont, Wolf-Walther,Kowalsky, Wolfgang,Johannes, Hans-Hermann
, p. 5090 - 5093 (2013/01/15)
In an attempt to synthesize a novel homoleptic complex 3 from 2-methyl-3-phenylquinoxaline 1 and Ir(acac)3 for application as a triplet emitter in OLEDs (organic light-emitting diodes) no cyclometalation was observed. Instead, an annulation to 1-methyl-4-phenylpyrrolo[1,2-a]quinoxaline 2 was observed. Since pyrroloquinoxalines are potentially bioactive and few paths for their synthesis are known, selected reactions and conditions were investigated, suggesting Ir(acac)3 as catalyst and proving glycerol to be a reactant.
Addition of arylboronic acids to arylpropargyl alcohols en route to indenes and quinolines
Panteleev, Jane,Huang, Richard Y.,Lui, Erica K. J.,Lautens, Mark
supporting information; experimental part, p. 5314 - 5317 (2011/12/01)
A regio- and stereoselective rhodium-catalyzed synthesis of trisubstituted allylic alcohols is described. The utility of these synthons is demonstrated in a convenient synthesis of indenes and quinolines.
A multicomponent coupling sequence for direct access to substituted quinolines
Majumder, Suprlyo,Gipson, Kevin R.,Odom, Aaron L.
supporting information; experimental part, p. 4720 - 4723 (2009/12/22)
A titanium-catalyzed three-component coupling reaction can be used to generate tautomers of Af-aryl-1,3-dllmlnes. Simple treatment of these products with acetic acid leads to cyclization forming quinoline derivatives In a one-pot procedure. The primary am
Photochemical Synthesis. Conversion of o-Vinylthioanilides to Quinolines
Mayo, Paul de,Sydnes, Leiv K.,Wenska, Grazyna
, p. 1549 - 1556 (2007/10/02)
Quinoline derivatives are formed in fair to good yields when acetonitrile solutions of o-vinylthioanilides are irradiated with Pyrex-filtered light.The transformation is a singlet reaction and involves intramolecular cycloaddition of the thioamide, yielding unstable thietanes, as the initial step.In the case of o-(1-trans-propenyl)thioacetanilide (2a) the corresponding thietane has been detected by 1H NMR spectroscopy by irradiating a toluene solution of the compound at -78 deg C.The quantum yield of quinoline formation from 2a appeared to be solvent dependent.Concomitant with quinoline formation, triplet cis-trans isomerization of the vinyl moiety takes place.In the case of 2a the quantum yield for trans -> cis isomerization is 0.506.A variable-temperature 1H NMR study of 2,3-dimethylquinoline in toluene solution has also been performed.For the 2,3-dimethylquinoline-toluene complex the enthalpy and entropy of formation are -1.03 +/- 0.10 kcal/mol and -3.7 +/- 0.2 gibbs/mol, respectively.
