Preparation of Grignard reagents from magnesium metal under continuous flow conditions and on-line monitoring by NMR spectroscopy

Goldbach, Michel; Danieli, Ernesto; Perlo, Juan; Kaptein, Bernard; Litvinov, V. M.; Blümich, Bernhard; Casanova, Federico; Duchateau, Alexander L. L.

doi:10.1016/j.tetlet.2015.11.077

Cited by 53 publications

(41 citation statements)

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“…Duchateau and coworkers prepared Grignard reagents under continuous flow conditions with online NMR spectroscopy. [54] Cronin and coworkers [55] presented a platform for synthetic chemistry incorporating an inline benchtop NMR spectrometer that is capable of monitoring and controlling reactions in real-time as shown in Figure 4. Ley and coworkers [56] recently reported a setup for the continuous processing and in situ reaction monitoring of hypervalent iodine(III)-mediated cyclopropanation using benchtop NMR spectroscopy as shown in Figure 5.…”

mentioning

confidence: 99%

Online Monitoring of Polymerizations: Current Status

Haven

Junkers

2017

Eur J Org Chem

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mentioning

confidence: 99%

Online Monitoring of Polymerizations: Current Status

Haven

Junkers

2017

Eur J Org Chem

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“…It continues to be used efficiently today in many other synthetic methodologies (SZUROMI, 2000, GOLDBACH et al, 2016, GAIR et al, 2016, FREITAS et al, 2011. Its application as a mediator of transesterification reactions, listed in Table 1 ( entries 1-25), served as a model for obtaining the best experimental conditions for the synthesis of 1-ethylpropyl-2-methyl-3-oxopentanoate (10), the intermediate ester in the synthesis of sitophilate.…”

Section: Resultsmentioning

confidence: 99%

TRANSESTERIFICATION REACTIONS WITH Mg0/I2 FOR THE SYNTHESIS OF SITOPHILATE, (2R, 3S) 1-ETHYLPROPYL-2-METHYL-3-HYDROXYPENTANOATE, AN AGGREGATION PHEROMONE FOR SITOPHILUS GRANARIUS LINNAEUS, 1785 (COLEOPTERA: CURCULIONIDAE)

Freitas

Silva

et al. 2016

HOLOS

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The concern to minimize the environmental impacts caused by the use of pesticides in agriculture has led researchers to develop new pest control methods. Thus, the technology based on the use of pheromones has been noted for being highly specific substances, that is act only on individuals of the same species. In this context, we describe the synthesis of sitophilate, aggregation pheromone of Sitophilus granarius, a important pest of stored cereal grains. The sitophilate was obtained by transesterification of methyl-2-methyl-3-oxopentanoate with 3-pentanol mediated by Mg 0 /I2, with subsequent reduction of the ketone group of 1-ethylpropyl-2-methyl-3-oxopentanoate using NaBH4 in the presence of a Lewis acid (ZnCl2, MgCl2, CaCl2 and MnCl2). The experimental results showed that the MnCl2 is the most effective for the formation of syn diastereoisomers, since these are the compounds that exert biological activity on the insect. KEYWORDS:Synthesis, pheromone, sitophilate, Sitophilus granarius, -keto ester. REAÇÕES DE TRANSESTERIFICAÇÃO COM Mg /I2 MEDIANDO À SÍNTESE DO SITOFILATO, (2R*, 3S*)-2-METIL-3-HIDROXIPENTANOATO DE 1-ETILPROPILA, FEROMÔNIO DE AGREGAÇÃO DO SITOPHILUS GRANARIUS LINNAEUS, 1785 (COLEOPTERA: CURCULIONIDAE) RESUMOA preocupação em minimizar os impactos ambientais ocasionado pelo uso de agrotóxicos na agricultura tem levado pesquisadores a desenvolver novos métodos de controle de pragas. Assim, a tecnologia baseada no uso de feromônios tem se destacado por serem substâncias altamente específicas, ou seja, agem apenas sobre indivíduos de uma mesma espécie. Neste contexto, descrevemos a síntese do sitofilato, feromônio de agregação do Sitophilus granarius, uma importante praga de grãos de cerais armazenados. O sitofilato foi obtido através da transesterificação do 2-metil-3-oxopentanoato de metila com 3-Pentanol mediada por Mg 0 /I2, com posterior redução do grupo cetona do 2-metil-3-oxopentanoato de 1-etilpropila utilizando NaBH4 na presença de um ácido de Lewis (ZnCl2, MgCl2, CaCl2 e MnCl2). Os resultados experimentais mostraram que o MnCl2 é o mais efetivo para a formação dos diastereoisômeros syn, uma vez que estes compostos são os que exercem atividade biológica no inseto.

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“…One interesting feature with flow chemistry is the possibility to perform in‐line analyses or quality control. Thus, Duchateau and his group reported the preparation of Grignard reagents in flow condition monitoring the quality of the reagents formed with on‐line NMR ( Figure ) . For their set up, they filled a column with Mg particles ranging in size from 100 to 1000 μm.…”

Section: Magnesium Derivativesmentioning

confidence: 99%