Microwave-Assisted [3 + 2] Cycloadditions of Azomethine Ylides

Bashiardes, George; Safir, Imad; Mohamed, Achmet Said; Barbot, F.; Laduranty, J.

doi:10.1021/ol0361195

Cited by 51 publications

(23 citation statements)

References 8 publications

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“…[18,1920] Imines 8 (R 1 = Ph) do not react under thermal conditions, so the use of the more reactive iminium cations type 10 is recommended in this case. [21,22,23,24,25,26] [a] Laboratório de Química Biorgânica, Núcleo Considering both strategies, there are two difficulties to overcome. In the first route, the resulting imine 8 is, in some cases, unstable, and in the second one, N-alkyl amino esters 9 have to be prepared.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Chromen[4,3‐b]pyrrolidines by Intramolecular 1,3‐Dipolar Cycloadditions of Azomethine Ylides: An Experimental and Computational Assessment of the Origin of Stereocontrol

et al. 2015

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Azomethine ylides, generated from imines derived Ocynnamyl or O-crotonyl salicylaldeyde and α-amino acids, undergo intramolecular 1,3-dipolar cycloaddition, leading to chromene-[4,3-b]-pyrrolidines. Two reaction conditions are used: a) microwave irradiation (200W) assisted heating (185 ºC) of a neat mixture of reagents, and b) conventional heating (170 ºC) in PEG-400 as solvent. In both cases mixture of two epimers at the α-position of the nitrogenatom in the pyrrolidine nucleus was formed through the less energetic endo-approach (B/C ring fusion). In many cases, the formation of the stereoisomer bearing a transarrangement into the B/C ring fusion in high proportions. A comprehensive computational and kinetic simulation studies are detailed. The analysis of the stability of transient 1,3-dipoles, followed by the assessment of intramolecular pathways and kinetic are carefully performed.

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Section: Introductionmentioning

confidence: 99%

Synthesis of Chromen[4,3‐b]pyrrolidines by Intramolecular 1,3‐Dipolar Cycloadditions of Azomethine Ylides: An Experimental and Computational Assessment of the Origin of Stereocontrol

et al. 2015

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“…Except for the entry 7, the major products presented fusion cis between the benzopiranic (B) and pirrolidinic (C) rings. 2 The major products in each reaction could be enriched after column chromatography. The structure of the major product of entry 1 was confirmed by X-ray of N-tosylated derivative 3 (Scheme 2).…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Aza-Pterocarpan Analogues via 1,3 Intramolecular Dipolar Cycloadditions in in situ generated Iminoolefins

Barcellos¹,

Dias²,

Sansano³

et al. 2013

Proceedings of the 15th Brazilian Meeting on Organic Synthesis Proceedings

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“…48 To a solution of K 2 CO 3 (1.5 mmol) and salicylaldehyde (0.5 mmol) in 3 mL of dry DMF, (R)-4-phenylbut-3-yn-2-yl methanesulfonate 3a in DMF (2 mL) was added dropwise. The reaction mixture was stirred at room temperature for 6 h and subsequently cooled to 0°C.…”

Section: General Methodsmentioning

confidence: 99%

Utilization of whole cell mediated deracemization in a chemoenzymatic synthesis of enantiomerically enriched polycyclic chromeno[4,3-b] pyrrolidines

Saravanan¹,

Jana²,

Chadha³

2014

Org. Biomol. Chem.

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Various aryl and alkyl substituted optically pure propargyl alcohols were obtained with excellent ee (up to >99%) and isolated yields (up to 87%) by deracemization using whole cells of Candida parapsilosis ATCC 7330. The whole cells show substrate specificity towards alkyl substituted propargyl alcohols and a switch in the enantioselectivity has been observed from 'R' to 'S' upon increasing the chain length. For the first time, enantiopure (R)-4-(3-hydroxybut-1-ynyl)benzonitrile, (R)-4-(biphenyl-4-yl)but-3-yn-2-ol, (S)-ethyl 3-hydroxy-5-phenylpent-4-ynoate and (S)-4-phenylbut-3-yne-1,2-diol were obtained using this strategy. Optically pure propargyl alcohol thus obtained was used as a chiral starting material in the synthesis of enantiomerically enriched poly-substituted pyrrolidines and a pyrrole derivative successfully demonstrating a chemoenzymatic route.

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Microwave-Assisted [3 + 2] Cycloadditions of Azomethine Ylides

Cited by 51 publications

References 8 publications

Synthesis of Chromen[4,3‐b]pyrrolidines by Intramolecular 1,3‐Dipolar Cycloadditions of Azomethine Ylides: An Experimental and Computational Assessment of the Origin of Stereocontrol

Synthesis of Chromen[4,3‐b]pyrrolidines by Intramolecular 1,3‐Dipolar Cycloadditions of Azomethine Ylides: An Experimental and Computational Assessment of the Origin of Stereocontrol

Synthesis of Aza-Pterocarpan Analogues via 1,3 Intramolecular Dipolar Cycloadditions in in situ generated Iminoolefins

Utilization of whole cell mediated deracemization in a chemoenzymatic synthesis of enantiomerically enriched polycyclic chromeno[4,3-b] pyrrolidines

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