Stereoselective Intermolecular [2 + 2] Cycloadditions of Erlenmeyer–Plöchl Azlactones Using Visible Light Photoredox Catalysis

Marra, Isabellar F S; Almeida, Angelina M. de; Silva, Larissa P; Castro, Pedro P. de; Corrêa, Charlane C.; Amarante, Giovanni W.

doi:10.1021/acs.joc.8b02430

Cited by 24 publications

(25 citation statements)

References 33 publications

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“…In 2018, the first intermolecular [2+2] photocyclization of Erlenmeyer–Plöchl Azlactones 36 for the synthesis of 1,2‐diaminotruxinic acid derivatives 37 was studied by Amarante group [36] . In an optimized protocol including Eosin Y and blue LED irradiation, various bicyclic spiro‐type cyclobutanes 37 were produced with moderate to good yields and perfect diastereocontrol, achieving just one diastereomer (1,2‐ Z , E ‐ anti ) in all cases (Scheme 20).…”

Section: [2+2] Cycloaddition Crafting Four Membered Ringsmentioning

confidence: 99%

Recent Visible Light and Metal Free Strategies in [2+2] and [4+2] Photocycloadditions

2021

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When aiming to synthesize molecules with elevated molecular complexity starting from relatively simple starting materials, photochemical transformations represent an open avenue to circumvent analogous multistep procedures. Specifically, lightmediated cycloadditions remain as powerful tools to generate new bonds begotten from non-very intuitive disconnections, that alternative thermal protocols would not offer. In response to the current trend in both industrial and academic research pointing towards green and sustainable processes, several strategies that meet these requirements are currently available in the literature. This Minireview summarizes [2 + 2] and [4 + 2] photocycloadditions that do not require the use of metal photocatalysts by means of alternative strategies. It is segmented according to the cycloaddition type in order to give the reader a friendly approach and we primarily focus on the most recent developments in the field carried out using visible light, a general overview of the mechanism in each case is offered as well.

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Section: [2+2] Cycloaddition Crafting Four Membered Ringsmentioning

confidence: 99%

Recent Visible Light and Metal Free Strategies in [2+2] and [4+2] Photocycloadditions

2021

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“…Last year, our research group described a highly regio‐ and diastereoselective [2+2]‐photocycloadditions of oxazolones through visible light photoredox methodology . By changing the photocatalyst (transition metal or organic dye), it was possible to attain both symmetric and nonsymmetric cyclobutane derivatives (Scheme A).…”

Section: Cycloadditionsmentioning

confidence: 99%

Recent Advances in Azlactone Transformations

2019

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Azlactones, also known as oxazolones, are versatile building blocks in organic synthesis due to the presence of multiple pro‐nucleophilic and electrophilic reactive sites. Recently, several elegant organo‐ and metal‐catalyzed studies have been described, allowing the stereocontrolled access to complex structures in only one or a few chemical steps. Moreover, the development of one‐pot, tandem and domino reactions greatly enhanced the azlactone scaffold potential. In this context, this review aims to cover novel methodologies, including a brief overview of oxazolones and Erlenmeyer azlactones preparation. New approaches towards classical reactions, such as dynamic kinetic resolution, cycloadditions, and conjugate additions will be presented as well as new methodologies involving photochemical and flow chemistry technology. Finally, for most studies, selected examples will be presented and mechanistic pathways and/or activating modes will be carefully discussed.

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“…Over the last years our research group has prepared several complex amino acid derivatives, some of them with promising biological activity. 17,18 Thus, we envisioned that the preparation of new derivatives by the coupling of a carbamate and an amino acid moiety would result in new derivatives with potential applications in cancer treatment. Besides, the modification of the amino acids employed, associated with carboxyl group functionalization by different amines, would allow the access to several biologically promising stable amide derivatives.…”

Section: Introductionmentioning

confidence: 99%

Cytotoxic Activity of Synthetic Chiral Amino Acid Derivatives

Castro

Siqueira

Conforte

et al. 2020

J. Braz. Chem. Soc.

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Cancer is a chronic degenerative disease considered one of the most important causes of death worldwide. In this context, a series of dual-protected amino acid derivatives was synthesized and evaluated as potential novel anticancer agents. The 40 derivatives were prepared in up to three reaction steps. The cytotoxic activities were screened in vitro against a panel of tumor and nontumor cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Among the synthesized derivatives, three of them showed promising activity against cancer cells with half-maximal inhibitory concentration (IC 50) ranging between 1.7-6.1 µM. The most promising derivative, bearing both a lipophilic N-alkyl diamine moiety and a protected amino acid scaffold showed a selectivity index of 3.4 towards tumor cells. The N-alkyl diamine moiety seems to play a crucial role in the enhancement of the anticancer activity. On the other hand, the incorporation of an amino acid scaffold resulted in increase in the selectivity towards cancer cell lines.

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Stereoselective Intermolecular [2 + 2] Cycloadditions of Erlenmeyer–Plöchl Azlactones Using Visible Light Photoredox Catalysis

Cited by 24 publications

References 33 publications

Recent Visible Light and Metal Free Strategies in [2+2] and [4+2] Photocycloadditions

Recent Visible Light and Metal Free Strategies in [2+2] and [4+2] Photocycloadditions

Recent Advances in Azlactone Transformations

Cytotoxic Activity of Synthetic Chiral Amino Acid Derivatives

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