Real-time monitoring of a cobalt-mediated one-pot transition metal-catalyzed multicomponent reaction

Crotti, Antônio Eduardo Miller; Previdi, Daniel; Donate, Paulo Marcos; McIndoe, J. Scott

doi:10.1016/j.ica.2020.119654

Cited by 5 publications

(7 citation statements)

References 42 publications

(44 reference statements)

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“…The investigation also showed that Co 2 + was responsible for undesired transformations; that is, side hydrodehalogenations occurred in the presence of Co 2 + as evidenced by the MS monitoring. Previous mechanism proposals have failed to consider this Co 2 + catalyzed side reaction but, as pointed out by the authors, [101] it represents a major part of the MCR global mechanism.…”

Section: New and General Mcrsmentioning

confidence: 99%

How and Why to Investigate Multicomponent Reactions Mechanisms? A Critical Review

Rodrigues

Eberlin

Neto

2021

The Chemical Record

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We review the most innovative efforts and greatest challenges faced when elucidating multicomponent reactions (MCRs) mechanisms. When compared to traditional reactions, the often two or more concurrent reactions pathways and the greater number of possible intermediates in MCRs turn their mechanistic investigation both a harder and trickier task. The common approaches used to investigate reaction mechanisms are often unable to clarify MCRs mechanisms; hence few but clever approaches are currently used to determine these mechanisms and to depict their key transformations. Their complexity has required most innovative approaches and the use of a number of unique techniques that have shed light over the favored pathway selected from the myriad of alternatives theoretically available for MCRs. This review focuses on the most successful efforts applied by a few leading groups to perform these puzzlingly investigations.

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Section: New and General Mcrsmentioning

confidence: 99%

How and Why to Investigate Multicomponent Reactions Mechanisms? A Critical Review

Rodrigues

Eberlin

Neto

2021

The Chemical Record

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“…Electrospray ionization mass spectrometry (ESI‐MS) monitoring 32–35 has been established as powerful tool to study reaction mechanism due to its ability to provide continuous and in situ snapshots of the changing composition of ionic species present in reaction solutions. ESI has also been able to transfer, with great gentleness, speed, and sensitivity, many ionic reaction intermediates to the gas phase for MS characterization 36–41 . Due to direct and rapid action, ESI has also been efficient in transferring even most short‐lived intermediates to the gas phase for MS(/MS) characterization.…”

Section: Introductionmentioning

confidence: 99%

“…Due to direct and rapid action, ESI has also been efficient in transferring even most short‐lived intermediates to the gas phase for MS(/MS) characterization. Many organic reactions or the action of different metal catalysis have been therefore extensively investigated via ESI‐MS allowing “ion fishing” 36–41 of multiple intermediates and products 17,42,43 …”

Section: Introductionmentioning

confidence: 99%

“…ESI has also been able to transfer, with great gentleness, speed, and sensitivity, many ionic reaction intermediates to the gas phase for MS characterization. [36][37][38][39][40][41] Due to direct and rapid action, ESI has also been efficient in transferring even most shortlived intermediates to the gas phase for MS(/MS) characterization.…”

Section: Introductionmentioning

confidence: 99%

“…Many organic reactions or the action of different metal catalysis have been therefore extensively investigated via ESI-MS allowing "ion fishing" [36][37][38][39][40][41] of multiple intermediates and products. 17,42,43 Considering the relevance of indole N-methylation by DMC, and To rationalize the absence of 5 in the reaction media, and the exclusive and predominant intermediate 8, theoretical calculations at the B3LYP-D3/6-311+G(d,p) level were performed.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Unveiling the mechanism of N‐methylation of indole with dimethylcarbonate using either DABCO or DBU as catalyst

et al. 2021

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Depending on the catalyst used, N‐methylation of indole with dimethylcarbonate (DMC)—an environmentally friendly alkylation agent—yields different products. With 1,4‐diazabicyclo[2.2.2]octane (DABCO), the reaction forms only N‐methylated indole, but with 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU), both N‐methylated and N‐methoxycarbonylated indole are formed. Using direct ESI(+)‐MS monitoring to collect actual snapshots of the changing ionic composition of the reaction solution, we report on the interception and characterization of key intermediates for such reactions. Although a mechanism has been proposed with methoxycarbonylated base as the key intermediate for both DBU and DABCO, the ESI(+)‐MS data and B3LYP‐D3/6‐311+G** calculations suggest that the reaction of DMC with indole under either DABCO or DBU catalysis follows contrasting mechanisms.

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A novel approach to study catalytic reactions via electrophoretic NMR on the example of Pd/NHC‐catalyzed Mizoroki–Heck cross‐coupling reaction

Kulikovskaya

Denisova

Ananikov

2022

Magnetic Reson in Chemistry

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Investigation of catalytic reactions using nuclear magnetic resonance (NMR) is a crucial task, which is often challenging to perform due to rather complex transformations at the metal center. In this work, it was shown that electrophoretic NMR can be a suitable method for studying catalytic reactions and for observing the changes in the catalyst nature. As an important example involving palladium catalysts with N‐heterocyclic carbine ligands (NHCs), the breakage of the Pd‐NHC bond can occur during the catalytic process. Electrophoretic NMR allows the distinction of compounds in the spectra depending on the charge, thus bringing new opportunities to mechanistic studies. Here, we present independent evidence of R‐NHC product formation in the Pd‐catalyzed Mizoroki–Heck reaction—the key process for catalyst change from the molecular to nano‐scale type.

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Real-time monitoring of a cobalt-mediated one-pot transition metal-catalyzed multicomponent reaction

Cited by 5 publications

References 42 publications

How and Why to Investigate Multicomponent Reactions Mechanisms? A Critical Review

How and Why to Investigate Multicomponent Reactions Mechanisms? A Critical Review

Unveiling the mechanism of N‐methylation of indole with dimethylcarbonate using either DABCO or DBU as catalyst

A novel approach to study catalytic reactions via electrophoretic NMR on the example of Pd/NHC‐catalyzed Mizoroki–Heck cross‐coupling reaction

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