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. 2022 Apr 6;12(17):10701-10710.
doi: 10.1039/d2ra01190e. eCollection 2022 Mar 31.

The development of imin-based tandem Michael-Mannich cyclocondensation through a single-electron transfer (SET)/energy transfer (EnT) pathway in the use of methylene blue (MB+) as a photo-redox catalyst

Farzaneh Mohamadpour  1
Affiliations

The development of imin-based tandem Michael-Mannich cyclocondensation through a single-electron transfer (SET)/energy transfer (EnT) pathway in the use of methylene blue (MB+) as a photo-redox catalyst

Farzaneh Mohamadpour. RSC Adv. .

Abstract

A four-component green tandem approach for the metal-free synthesis of polyfunctionalized dihydro-2-oxypyrroles was devised using the Michael-Mannich cyclocondensation of amines, dialkyl acetylenedicarboxylaes, and formaldehyde. Photo-excited state functions generated from methylene blue (MB+) were employed as single-electron transfer (SET) and energy transfer (EnT) catalysts at ambient temperature in an ethanol solvent, employing visible light as a renewable energy source in the air atmosphere. This study aims to increase the usage of a non-metal cationic dye that is both inexpensive and widely available. Methylene blue is photochemically produced with the least amount of a catalyst due to its high yields, energy-effectiveness, high atom economy, time-saving features of the reaction, and operational simplicity. As a result, a variety of ecological and long-term chemical features are achieved. Surprisingly, such cyclization can be done on a gram scale, implying that the process has industrial potential.

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Conflict of interest statement

There are no conflicts to declare.

Figures

Scheme 1
Scheme 1. Polyfunctionalized dihydro-2-oxypyrroles synthesized.
Fig. 1
Fig. 1. Photocatalysts were put to the test in this study.
Scheme 2
Scheme 2. Control studies that are important for understanding the mechanism of aniline (1 and 3, 2 mmol), dimethyl acetylenedicarboxylate (DMAD) (2, 1 mmol), and formaldehyde (4, 1.5 mmol) reactions.
Scheme 3
Scheme 3. The proposed mechanistic pathway to synthesize the polyfunctionalized dihydro-2-oxypyrroles.
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References

    1. Patel R. I. Sharma A. Sharma S. Sharma A. Org. Chem. Front. 2021;8:1694–1718. doi: 10.1039/D0QO01182G. - DOI
    1. Politano F. Oksdath-Mansilla G. Org. Process Res. Dev. 2018;22:1045–1062. doi: 10.1021/acs.oprd.8b00213. - DOI
    1. Verschueren R. H. de Borggraeve W. M. Molecules. 2019;24:2122–2160. doi: 10.3390/molecules24112122. - DOI - PMC - PubMed
    1. Wainwright M. Crossley K. B. J. Chemother. 2002;14:431–443. doi: 10.1179/joc.2002.14.5.431. - DOI - PubMed
    1. Tardivo J. P. del Giglio A. de Oliveira C. S. Gabrielli D. S. Junqueira H. C. Tada D. B. Severino D. de Fátima Turchiello R. Baptista M. S. Photodiagn. Photodyn. Ther. 2005;2:175–191. doi: 10.1016/S1572-1000(05)00097-9. - DOI - PubMed