Pyrrole synthesis using a tandem Grubbs’ carbene–RuCl3 catalytic system

Dieltiens, Nicolai; Stevens, Christian V.; Vos, David; Allaert, Bart; Drozdzak, Renata; Verpoort, Francis

doi:10.1016/j.tetlet.2004.10.044

Cited by 76 publications

(42 citation statements)

References 14 publications

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“…However, it is reasonable to assume that, at least for 1-(prop-1-enyl)benzene and cis-1,4-diphenyl-1-butene, the substrate is subjected to a double-bond migration and thereafter enters the catalytic cycle. [38] Encouraged by these results we also verified the isomerization by using in situ IR spectroscopy which monitors reactions in real-time. This technique is very appropriate to characterize components that are difficult to isolate (in situ advantage).…”

Section: Cross-metathesis (Cm)supporting

confidence: 52%

New Indenylidene‐Schiff Base‐Ruthenium Complexes for Cross‐Metathesis and Ring‐Closing Metathesis

Vila¹,

Monsaert²,

Drozdzak³

et al. 2009

Adv Synth Catal

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We here report on the stability and catalytic activity of new indenylidene-Schiff base-ruthenium complexes 3a-f through representative cross-metathesis (CM) and ring-closing metathesis (RCM) reactions. Excellent activity of the new complexes was found for the two selected RCM reactions; prominent conversion was obtained compared to the commercial Hoveyda-Grubbs catalyst 2. Moreover, excellent results were obtained for a standard CM reaction. Higher conversions were achieved with one of the indenylidene catalysts compared with HoveydaGrubbs catalyst. Unexpectedly, an isomerization reaction was observed during the CM reaction of allylbenzene. To the best of our knowledge, isomerization reactions in this model CM reaction in closed systems have never been described using first generation catalysts, including the Hoveyda-Grubbs catalyst. The first model CM reactions as well as the RCM reactions have been monitored using 1 H NMR. The course of the CM reaction of 3-phenylprop-1-ene (8) and cis-1,4-diacetoxybut-2-ene (9) was monitored by GC. The isomerization reaction was studied by means of GC-mass spectrometry and in situ IR spectroscopy. All catalysts were structurally characterized by means of 1 H, 13 C, and 31 P NMR spectroscopy.

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Section: Cross-metathesis (Cm)supporting

confidence: 52%

New Indenylidene‐Schiff Base‐Ruthenium Complexes for Cross‐Metathesis and Ring‐Closing Metathesis

Vila¹,

Monsaert²,

Drozdzak³

et al. 2009

Adv Synth Catal

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“…Derivatives 16 were also cleanly converted to the pyrrolines but could, as we have described before, not be oxidized to the pyrroles because of the electron-withdrawing substituent on nitrogen (Table 2). [29] Looking at the reaction mechanism, two pathways are possible (Scheme 5 [13] reported that when working under "Moris conditions" [30] ethylene gas reacts with carbenoids of type 29 in a second catalytic cycle producing the metathesis products and thus explaining the dramatic effect of ethylene on both the yield and the reaction rate of Rucatalyzed enyne RCM reactions. As our experiments were performed under an inert nitrogen atmosphere, the fact that complete conversion is observed within 30 minutes tends to rule out the possibility of the ene-then-yne pathway, as this would contradict the low yields of enyne metathesis that predate Moris observations.…”

Section: Resultsmentioning

confidence: 99%

Enyne Metathesis–Oxidation Sequence for the Synthesis of 2‐Phosphono Pyrroles: Proof of the “Yne‐then‐Ene” Pathway

Dieltiens

Moonen

Stevens

2006

Chemistry A European J

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A new tandem reaction sequence has been developed for the synthesis of 2‐phosphono pyrroles. The sequence consists of ring‐closing enyne metathesis of a substituted aminophosphonate, containing a terminal alkyne and an internal alkene, in combination with in situ oxidation of the produced 3‐pyrrolines using tetrachloroquinone. By analyzing the formation of the end and certain byproducts, taking into account the difference in reactivity of different substrates and carefully studying spectroscopic data, it was found that the reaction proceeds by means of the “yne‐then‐ene” pathway. During the initiation phase, a new ruthenium carbene is formed which continues the propagation cycle.

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“…The group of Stevens has reported a straightforward pyrrole synthesis from diallylamines by way of a tandem RCM/dehydrogenation reaction using a combination of Grubbs catalyst 3 and RuCl 3 (Scheme 37). [66] The ultrasonic bath is expected to favour the formation of a fine dispersion of RuCl 3 ·x H 2 O in the reaction mixture, thus greatly increasing its active surface, and consequently the efficiency of the dehydrogenation step.…”

Section: Ruthenium-catalyzed Metathesis Of Amines A-substituted By Anmentioning

confidence: 99%

Olefin Metathesis of Amine‐Containing Systems: Beyond the Current Consensus

Compain¹

2007

Adv Synth Catal

163

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Olefin metathesis is one of the most powerful synthetic tool to access amine-containing heterocycles and alkaloids. A major drawback associated with the use of amines concerns their ability to coordinate to metal-alkylidene complexes and to interfere unproductively with catalytic activity. Based on literature precedents, it has been established as a "dogma" that efficient metathesis reactions are suppressed in the presence of basic amines and that such substrates must invariably be deactivated by conversion of the amines to the corresponding carbamates or ammonium salts. However, an increasing number of examples of amine-containing compounds that are good substrates for metathesis is being reported in the literature. How can this "non-classical" reactivity be rationalized and exploited? The purpose of this review is to provide an overview of successful metathesis reactions performed with aminecontaining compounds in order to allow some guidelines to be formulated. A special emphasis is placed on the different parameters that may influence the outcome of the reaction such as steric effects, amine basicity, and the nature of the catalyst.

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Pyrrole synthesis using a tandem Grubbs’ carbene–RuCl3 catalytic system

Cited by 76 publications

References 14 publications

New Indenylidene‐Schiff Base‐Ruthenium Complexes for Cross‐Metathesis and Ring‐Closing Metathesis

New Indenylidene‐Schiff Base‐Ruthenium Complexes for Cross‐Metathesis and Ring‐Closing Metathesis

Enyne Metathesis–Oxidation Sequence for the Synthesis of 2‐Phosphono Pyrroles: Proof of the “Yne‐then‐Ene” Pathway

Olefin Metathesis of Amine‐Containing Systems: Beyond the Current Consensus

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