Organo Photoinduced Decarboxylative Alkylation of Coumarins with <i>N</i>-(Acyloxy)phthalimide

Tripathi, Krishna N.; Belal, Md.; Singh, Ravi P.

doi:10.1021/acs.joc.9b00977

Cited by 46 publications

(29 citation statements)

References 59 publications

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“…Besides the 3‐alkyl coumarins, the synthesis of 4‐alkyl coumarins was reported by Singh's groups in which 3‐cynocoumarins 114 and Eosin Y were employed as substrates and photocatalyst, affording the C‐4 alkylated coumarins 115 in moderate to good yields (Scheme 36). [66] The primary alkyl (cyclic and acyclic) N ‐hydroxyphthalimide esters actively participated, delivering the respective 4‐alkylated‐3‐cynocoumarins 115 in moderate to excellent yields. On the other hand, the tertiary and secondary (except 115 c ) alkyl N ‐hydroxyphthalimide esters afforded the different products (4‐alkyl‐3‐cyno‐2‐chromanoes) 116 in moderate to good yields.…”

Section: Functionalization Of Coumarin Scaffold (Coumarins As Substrates)mentioning

confidence: 99%

Visible Light‐Induced Synthesis of Functionalized Coumarins

Singh

Sharma

2021

Adv Synth Catal

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Functionalized coumarins are privileged scaffolds which display diverse pharmacological and physiological activities, and a myriad of applications in medical science and biomedical research. Owing to these multifarious activities of coumarins, synthetic chemists are actively engaged in developing new and superior methods for their synthesis. In the last decade, the synthesis of functionalized coumarins via visible light-induced methodologies has turned into one of the most significant and fundamental missions in organic synthesis. This review covers the literature on the synthesis of functionalized coumarins under visible light-assisted methodologies. 3.6. 4-Chloro-3-Nitrocoumarin as Substrate 3.7. 1-Bromo-2H-Phenaleno[1,2,3-de]chromen-2-Ones as Substrate 4.Conclusions

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Section: Functionalization Of Coumarin Scaffold (Coumarins As Substrates)mentioning

confidence: 99%

Visible Light‐Induced Synthesis of Functionalized Coumarins

Singh

Sharma

2021

Adv Synth Catal

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“…Site-selective alkylation of heteroaromatics has always been of great value and challenge. For example, Singh's group [144] realized the C-4 alkylation of coumarins with NHP esters 1 in 2019 (Scheme 34a). Interestingly, the NHP esters derivated from primary carboxylic acids provide the C-4 alkylated coumarins, while the NHP esters from secondary and tertiary carboxylic acids gave C-4 alkylated 3,4-dihydrocoumarins.…”

Section: Reactions Involving Eosin Y (Ey)mentioning

confidence: 99%

Advances of N-Hydroxyphthalimide Esters in Photocatalytic Alkylation Reactions

He¹,

Li²,

Chen³

et al. 2021

Chinese Journal of Organic Chemistry

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N-Hydroxyphthalimide (NHP) esters are easily available, stable, inexpensive, and highly photoactive compounds, which are derived from the corresponding carboxylic acids. In recent years, the application of NHP esters in photocatalytic decarboxylative reactions has captured huge attention. Herein, the vigorous development of photocatalytic alkylation reactions using alkyl NHP esters as alkylating reagents is summarized based on the classification of photocatalysts.

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“…Recently, Singh reported an organophotoredox catalyzed C4‐alkylation of coumarins 39 using N ‐(acyloxy)phthalimides 5 as the source of alkyl radicals (Scheme 25). [61] Interestingly, primary carboxylic acid derived NHPI esters produced 4‐alkylated‐3‐substituted coumarins 40 ; whereas, in the case of secondary and tertiary alkyl‐NHPI esters corresponding chromanone derivatives were obtained. The utility of the method was showcased through alkylation of coumarin using NHPI esters of natural products and drug carboxylic acids.…”

Section: C−h Functionalization Of Heteroarenesmentioning

confidence: 99%

Late‐Stage Alkylation of Heterocycles Using N‐(Acyloxy)phthalimides

Parida

Hota

Kumar

et al. 2021

Chemistry An Asian Journal

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Synthetic methods enabling late-stage modification of heterocycles hold tremendous importance in the pharmaceutical and agrochemical industry and drug discovery. Accordingly, efficient, functional group tolerant and selective late-stage alkylation of valuable molecular entities is of enormous significance and well-acknowledged in medicinal chemistry. Radical alkylation of heteroarenes employing carboxylic acids as the alkyl radical precursor represents one of the most direct ways of CÀ H functionalizations of heterocycles. Recently, the field has undergone a revolutionary development especially with regard to the generation of alkyl radicals under much milder conditions. In this regard N-(acyloxy)phthalimides (NHPI esters) have emerged as a suitable precursor of a diverse set of alkyl radicals allowing formal CÀ H alkylation of not only N-heteroarenes but a diverse set of non-aromatic heterocycles under visible light photocatalysis or electrochemical conditions. This review delineates all these discoveries and provides readers a comprehensive overview of this rapidly expanding field.

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Organo Photoinduced Decarboxylative Alkylation of Coumarins with N-(Acyloxy)phthalimide

Cited by 46 publications

References 59 publications

Visible Light‐Induced Synthesis of Functionalized Coumarins

Visible Light‐Induced Synthesis of Functionalized Coumarins

Advances of N-Hydroxyphthalimide Esters in Photocatalytic Alkylation Reactions

Late‐Stage Alkylation of Heterocycles Using N‐(Acyloxy)phthalimides

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