Lanthanide Chloride Catalyzed Imino Diels−Alder Reaction. One-Pot Synthesis of Pyrano[3,2-<i>c</i>]- and Furo[3,2-<i>c</i>]quinolines

马云,; 钱长涛,; 谢美华,; 孙杰,

doi:10.1021/jo982220p

Cited by 158 publications

(61 citation statements)

References 13 publications

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“…In this connection, much attention has been focused on three-component aza-Diels-Alder reactions involving aldehyde, amine, and either dihydropyran or dihydrofuran. A series of Lewis acids such as Ln-(OTf) 3 , [4] GdCl 3 , [5] molecular iodine, [6] TMSCl, [7] SbCl 3 , [8] and Selectfluor TM [9] have been found to be effective catalysts for this purpose. Normally, the process affords the products as mixtures of cis and trans isomers, in which the trans isomer is the major one in most cases.…”

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confidence: 99%

Stereoselective Synthesis of Pyrano[3,2‐c]‐ and Furano[3,2‐c]quinolines: Samarium Diiodide‐Catalyzed One‐Pot Aza‐Diels–Alder Reactions

Zhou

Han

et al. 2007

Eur J Org Chem

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Three-component aza-Diels-Alder reactions involving aromatic aldehydes, aromatic amines, and dihydropyran or dihydrofuran are effectively catalyzed by samarium diiodide to afford pyrano[3,2-c]-or furano [3,2-c]quinolines in good yields and with high stereoselectivities. Either the cis or the IntroductionThe tetrahydroquinoline skeleton exists in many natural or synthetic biologically active materials, and its derivatives are widely applied in the pharmaceutical and biochemical fields.[1] Some of them, such as pyrano-and furanoquinolines, have attracted special attention as a result of their high degrees of structural diversity and wide spectra of biological actions.[2] The [4+2] cycloaddition reactions between N-arylimines (heterodienes) and dihydropyran or dihydrofuran (dienophiles) under Lewis acid catalysis conditions have long been recognized as one of the most convenient methods for the synthesis of quinolines of this type and have been explored for catalysts, scope, and applications.[3] However, most of the imines used as starting materials are unstable, which leads to difficulties in their isolation and purification. In this connection, much attention has been focused on three-component aza-Diels-Alder reactions involving aldehyde, amine, and either dihydropyran or dihydrofuran. A series of Lewis acids such as Ln-(OTf) 3 , [4] GdCl 3 , [5] molecular iodine, [6] TMSCl, [7] SbCl 3 , [8] and Selectfluor TM [9] have been found to be effective catalysts for this purpose. Normally, the process affords the products as mixtures of cis and trans isomers, in which the trans isomer is the major one in most cases. It is noteworthy that the use of Lewis acids as catalysts in one-pot reactions to prepare the tetrahydroquinolines stereoselectively with particular preference for the cis isomers has met with limited success in the past. Kobayashi [4a] has reported the formation of furano[3,2-c]quinoline with 62 % cis selectivity using (polyallyl)scandium trifylamide ditriflate as a catalyst. More recently, Yadav [9] has demonstrated the utility of Selectfluor TM as a catalyst to generate about 90 % yields of cis pyrano-and furanoquinolines. Therefore, it is still necessary to develop new and efficient catalysts for stereoselective syntheses of tetrahydroquinolines to make better use of this one-pot synthesis methodology.On the other hand, SmI 2 has served as a Lewis acid-type precatalyst and has been applied to a variety of reactions. [10] In our ongoing research into developing SmI 2 as a precatalyst in organic synthesis, [11] we investigated one-pot iminoDiels-Alder reactions of aldehydes and amines with dihydropyran or dihydrofuran in the presence of catalytic amount of SmI 2 . It was found that SmI 2 was effective for this process and that the stereoselective synthesis of pyrano[3,2-c]-and furano[3,2-c]quinolines could conveniently be effected through control of the reaction conditions. We now wish to report on these results. Results and DiscussionTo select favorable reaction conditions, we first examined the model re...

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confidence: 99%

Stereoselective Synthesis of Pyrano[3,2‐c]‐ and Furano[3,2‐c]quinolines: Samarium Diiodide‐Catalyzed One‐Pot Aza‐Diels–Alder Reactions

Zhou

Han

et al. 2007

Eur J Org Chem

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“…The generality of the present protocol was then extended to trans (12), cis (13) isomers of tetrahydropyrano [3,2-c] quinoline. The reactions proceeded efficiently in 90% yield at ambient temperature.…”

Section: Resultsmentioning

confidence: 99%

“…Imines derived from aromatic amines act as heterodienes and undergo imino Diels-Alder reaction with various dienophiles. Some improved procedures have been reported for the reaction of 3,4-dihydro-2H-pyran (DHP) with aniline using BF3.OEt2 [11], GdCl3 [12], InCl3 [13], LiClO4 [14], ZrCl4 [15], TMSCl [16], I2 [17], SbCl3 [18], SbCl3-HPA [19], PMA [20], CF3CO2H [21].…”

Section: Introductionmentioning

confidence: 99%

Tin(II)chloride catalyzed synthesis of pyranoquinolines, phenanthridinone and phenanthridine derivatives

2011

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“…The physical data are in agreement with those reported in the literature. [24] Characterization: The X-ray analysis was performed with a Siemens D 5000 wide-angle goniometer. Scanning electron microscopy was performed with a JEOL CamScan 4 microscope using acceleration voltages between 15 and 20 kV.…”

Section: Methodsmentioning

confidence: 99%

Polymer Fibers as Carriers for Homogeneous Catalysts

Stasiak

Studer

Greiner

et al. 2007

Chemistry A European J

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This paper describes a polymer fiber-based approach for the immobilization of homogeneous catalysts. The goal is to generate products that are free of catalysts which would be of great importance for the development of optoelectronic or pharmaceutical compounds. Electrospinning was employed to prepare the non-woven fiber assembly composed of polystyrene. The homogeneous catalyst scandium triflate was immobilized on the polystyrene fibers during electrospinning and on corresponding core shell fibers using a fiber template approach. An imino aldol and an aza-Diels-Alder model reaction were carried out with each fibrous catalytic system. This resulted in the immobilization of homogeneous catalysts in a polymer environment without loss of their catalytic activity and may even be enhanced when compared with reactions carried out in homogeneous solutions.

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Lanthanide Chloride Catalyzed Imino Diels−Alder Reaction. One-Pot Synthesis of Pyrano[3,2-c]- and Furo[3,2-c]quinolines

Cited by 158 publications

References 13 publications

Stereoselective Synthesis of Pyrano[3,2‐c]‐ and Furano[3,2‐c]quinolines: Samarium Diiodide‐Catalyzed One‐Pot Aza‐Diels–Alder Reactions

Stereoselective Synthesis of Pyrano[3,2‐c]‐ and Furano[3,2‐c]quinolines: Samarium Diiodide‐Catalyzed One‐Pot Aza‐Diels–Alder Reactions

Tin(II)chloride catalyzed synthesis of pyranoquinolines, phenanthridinone and phenanthridine derivatives

Polymer Fibers as Carriers for Homogeneous Catalysts

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