[3+2]‐Cycloadditionen von Azoalkenen an Enamine – „criss‐cross”︁‐Cycloadditionen an Azoalkene

Sommer, Sven G.

doi:10.1002/ange.19790910929

Cited by 18 publications

(2 citation statements)

References 8 publications

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“…The spontaneous subsequent loss of the secondary amine results in the formation of the 1-aminopyrrole derivatives P4 (Scheme 8). [12] For the product investigations, we have chosen the reactions between 1 a,c and the 1-morpholinocycloalkenes 5 a,d in acetonitrile. The reactions of 1 a and 1 c with morpholinocyclohexene (5 a) delivered the 1-aminopyrroles 5 aa and 5 ac, respectively.…”

Section: Product Characterizationmentioning

confidence: 99%

Electrophilic Reactivities of 1,2‐Diaza‐1,3‐dienes

Kanzian

Nicolini

Crescentini

et al. 2010

Chemistry A European J

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The kinetics of the reactions of 1,2-diaza-1,3-dienes 1 with acceptor-substituted carbanions 2 have been studied at 20 °C. The reactions follow a second-order rate law, and can be described by the linear free energy relationship log k(20 °C)=s(N+E) [Eq. (1)]. With Equation (1) and the known nucleophile-specific parameters N and s for the carbanions, the electrophilicity parameters E of the 1,2-diaza-1,3-dienes 1 were determined. With E parameters in the range of -13.3 to -15.4, the electrophilic reactivities of 1a-d are comparable to those of benzylidenemalononitriles, 2-benzylideneindan-1,3-diones, and benzylidenebarbituric acids. The experimental second-order rate constants for the reactions of 1a-d with amines 3 and triarylphosphines 4 agreed with those calculated from E, N, and s, indicating the applicability of the linear free energy relationship [Eq. (1)] for predicting potential nucleophilic reaction partners of 1,2-diaza-1,3-dienes 1. Enamines 5 react up to 10(2) to 10(3) times faster with compounds 1 than predicted by Equation (1), indicating a change of mechanism, which becomes obvious in the reactions of 1 with enol ethers.

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Section: Product Characterizationmentioning

confidence: 99%

Electrophilic Reactivities of 1,2‐Diaza‐1,3‐dienes

Kanzian

Nicolini

Crescentini

et al. 2010

Chemistry A European J

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“…A more recent work [ 61 ] using density functional theory (DFT) studies, showed a polar character of the Diels–Alder reaction of nitrosoalkenes with enamines, being the two σ bonds formed in these polar cycloaddition reactions in a highly asynchronous concerted process. On the other hand reactions of azoalkenes with enamines are solvent and structure – of enamine and azoalkene - dependent [ 1 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 ], proceeding either via [4+2] cycloaddition or conjugate addition.…”

Section: Nitroso- and Azo-alkenesmentioning

confidence: 99%

Addition and Cycloaddition Reactions of Phosphinyl- and Phosphonyl-2H-Azirines, Nitrosoalkenes and Azoalkenes

Lemos

2009

Molecules

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Heteroring‐Annulated Pyrrolino‐Tetrahydroberberine Analogues

et al. 2017

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Af acile method for the synthesis of pyrrolino-tetrahydroberberine derivatives startingf rom 1,2-diaza-1,3dienes and dihydroberberines is reported. The synthesis is ac ascade reactioni nvolving aM ichael-typea ddition of the enaminem oiety of dihydroberberine to an azo-enes ystem, followed by nitrogen cyclization on the resulting iminium ion.[a] G.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under http://dx.Figure 2. Pyrrolo[2,3-b]pyridine core of chaetominines and kapakahines and of isoschizogaminea nd isoschizogaline. Scheme1.Retrosynthetic analysis of pyrrolo[2,3-b]pyridine systems.Scheme2.Synthesis of 7,8-dihydroberberine 2 [14] and of 8-acetonyl-7,8-dihydroberberine 3, [15] starting from commercial berberinechloride 1.Scheme3.Proposed mechanism for the synthesis of fused pyrrolino-THBderivative 6e.2 96 3 72[a] Isolated yields of fused pyrrolino-tetrahydroberberine derivatives 6.[ b] All of the reactionstook placewithin 0.25 h.

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[3+2]‐Cycloadditionen von Azoalkenen an Enamine – „criss‐cross”︁‐Cycloadditionen an Azoalkene

Cited by 18 publications

References 8 publications

Electrophilic Reactivities of 1,2‐Diaza‐1,3‐dienes

Electrophilic Reactivities of 1,2‐Diaza‐1,3‐dienes

Addition and Cycloaddition Reactions of Phosphinyl- and Phosphonyl-2H-Azirines, Nitrosoalkenes and Azoalkenes

Heteroring‐Annulated Pyrrolino‐Tetrahydroberberine Analogues

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