Stereoselective synthesis of pyrano[3,2‐c]‐ and furano[3,2‐c]quinolines: Gadolinium chloride catalyzed one‐pot aza–Diels–Alder reactions

Abstract

A simple and efficient method for the cis‐selective synthesis of pyrano‐ and furano[3,2‐c]quinolines via gadolinium chloride catalyzed one‐pot aza–Diels–Alder reaction is described. Solvent conditions played a major role in affecting the diastereoselectivity of the products. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:351–354, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20612

Progress in the Chemistry of Tetrahydroquinolines

“…For instance, 25 mol% of GdCl 3 triggered the three-component reaction to deliver excellent yields of the corresponding THQs 516 and 517 with good diastereoselectivity (Scheme 139). 255 In addition, Sc-(OTf) 3 , 256 BF 3 •OEt 2 , 257 NbCl 5 , 258,259 Sm(OTf) 3 , 260 ceric ammonium nitrate (CAN), 261 CeCl 3 •7H 2 O/NaI, 262 and Al-(OTf) 3 263 were also employed as catalysts for the same reaction. This chemistry was applied to the synthesis of hexahydro 2Hpyrano[3,2-c]quinolines as selective σ 1 receptor ligands.…”

Diastereoselective Synthesis of Pyranoquinolines on Zirconium‐Containing UiO‐66 Metal‐Organic Frameworks

“…Various homogeneous and heterogeneous acid catalysts, including SnCl 2 , SbCl 3 doped on hydroxyapatite (SbCl 3 ‐HPA), tungstophosphoric acid supported on nanosized MCM‐41 (TPA/MCM‐41), perchloric acid adsorbed on silica gel (HClO 4 ‐SiO 2 ), GdCl 3 , and ferric sulfate, have been reported for the synthesis of tetrahydropyranoquinolines. However, some of the methods used so far suffer from limitations such as the use of large amounts of catalyst (up to 50 mol‐%), very low diastereoselectivities, or poor catalyst reusability.…”

Reaction under Ball-Milling: Solvent- and Metal-Free One-Pot Diastereoselective Synthesis of Tetrahydroquinoline Derivatives as Potential Antibacterial and Anticancer Agents

“…In this connection, considerable attention has been focused on the development of one-pot three-component reactions involving amine, aldehyde, and either dihydrofuran or dihydropyran in different solvents using a variety of reagents/catalysts. [17][18][19][20][21][22][23][24][25][26][27] Usually, the process gives the products as a mixture of trans and cis isomers. Catalysts such as Lanthanide Chloride, 17a Fe 3+ -K-10 montmorillonite clay, 17b Trimethylsilyl chloride (Me3SiCl), 18a Antimony chloride doped on hydroxyapatite (SbCl3-HAP), 19a Antimony trichloride (SbCl3), 19b Vanadium(III) chloride (VCl3), 19c Phosphomolybdic Acid (PMA), 20 Samarium(II) iodide (SmI2), 21 Polyaniline-ptoluenesulfonate salt, 22a Ceric Ammonium Nitrate (CAN), 22b zirconium-containing UiO-66 metal-organic frameworks, 23 provided trans isomer as major product, while, Selectfluor TM , 24 [bmim]BF4, 25a Gadolinium(III) chloride (GdCl3) 26 , Samarium(III) trifluoromethanesulfonate Sm(OTf)3 27 and Polyaniline-ptoluenesulfonate salt, 22a catalysts offered cis isomer as major product in different solvents.…”