A concise and improved synthesis of (+)-eleutherin, (+)-allo-eleutherin and a formal synthesis of (+)-nocardione B

Fernandes, Rodney A.; Chavan, Vijay P.; Mulay, Sandip V.

doi:10.1016/j.tetasy.2011.02.011

Cited by 18 publications

(4 citation statements)

References 58 publications

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“…Scheme 3 An alternative synthesis of (+)-and (-)-juglomycin A 26,27 We have also considered concise enantioselective syntheses of (+)-eleutherin (2a) and (+)-allo-eleutherin (2b) as well as the formal synthesis of (+)-nocardione B (3) (Scheme 4). (+)-Eleutherin (2a) and (-)-isoeleutherin (ent-2b) were isolated from the bulbs of Eleutherin bulbosa 28 in 1950.…”

Section: Synthesis Of (+) and (-)-Juglomycin A (1) 2021mentioning

confidence: 99%

“…An improved synthesis of (+)-eleutherin (2a) and (+)allo-eleutherin (2b) was subsequently reported by us (Scheme 5). 27 The intermediate 39 was prepared as reported by us earlier (Scheme 4). With the success in obtaining the cis-isomer in the synthesis of demethoxycardinalin-3 using dry HCl gas 33 (this work is discussed later), we considered similar conditions for the synthesis of eleutherin, aiming for either diastereomer to be obtained as the major product.…”

Section: Synthesis Of (+)-Eleutherin (2a) (+)-Allo-eleutherin (2b)and a Formal Synthesis Of (+)-Nocardione B (3)mentioning

confidence: 99%

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A Decade with Dötz Benzannulation in the Synthesis of Natural Products

Fernandes

Kumari²,

Pathare

2020

Synlett

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The Dötz benzannulation is a named reaction that utilizes Fischer chromium carbenes in a formal [3+2+1] cycloaddition with an alkyne and CO to produce the corresponding benzannulated product. Since its development in the 1970s, this reaction has been extensively used in the synthesis of natural products and various molecular architectures. Although the reaction sometimes suffers from the formation of other competing side products, the rapid construction of naphthol structures with a 1,4-dihydroxy unit makes it the most appropriate reaction for the synthesis of p-naphthoquinones. This review focuses on our group’s efforts over the past decade on the extensive use of this annulation reaction along with the contributions of others on the synthesis of different natural products.1 Introduction2 General Description and Mechanism of the Dötz Benzannulation Reaction3 Applications of the Dötz Benzannulation in Natural Product Synthesis over the Last Decade4 Conclusion

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Section: Synthesis Of (+) and (-)-Juglomycin A (1) 2021mentioning

confidence: 99%

Section: Synthesis Of (+)-Eleutherin (2a) (+)-Allo-eleutherin (2b)and a Formal Synthesis Of (+)-Nocardione B (3)mentioning

confidence: 99%

A Decade with Dötz Benzannulation in the Synthesis of Natural Products

Fernandes

Kumari²,

Pathare

2020

Synlett

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“…In this context, Fernandes and co‐workers in 2011 reported the formal synthesis of (+)‐nocardione B ( 71) , (+)‐eleutherin 73 , and (+)‐allo‐eleutherin 74 . They initiated their synthesis from the Dötz benzannulation reaction using alkyne 65 (prepared from (S)‐ethyl‐3‐hydroxybutanoate) and the Fischer carbene complex 29 (prepared from 2‐bromoanisole) to deliver the naphthalene derivative 66 in respectable yield . After de‐protection of the TBDMS group from 66 , the alcohol 67 was obtained in excellent yield.…”

Section: Synthesis Of Natural Productsmentioning

confidence: 99%

The Dötz Benzannulation Reaction: A Booming Methodology for Natural Product Synthesis

2020

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Since its finding in 1975, the Dötz benzannulation reaction has attracted a great attention of the scientific community as it permits the regio‐controlled construction of functionalised aromatic frameworks from acyclic precursors. In recent years, this beautifully simple yet much powerful technique for the formation of C−C bonds has opened‐up new possibilities in modern synthetic organic chemistry. In this Review, we report the developments in natural products synthesis by employing the Dötz benzannulation as a key transformation. Although, a flow of publications have witnessed a constant progress in this wonderful area of research, but to our best knowledge this is the first review which purely focuses on the applications of the Dötz benzannulation reaction in natural product synthesis. We are assured that this review will act as a promoter in amplifying the applications of the Dötz benzannulation in the domain of synthetic organic chemistry.

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“…Additionally, eleutherol (1a) is an inhibitor of tyrosinase and melanin formation in vitro while eleutherin (1b) has been found to be a reversible inhibitor of topoisomerase II. [7][8][9] The incorporation of nitrogen into polyaromatic systems such as these can positively affect their biological activity by improving solubility and metabolic stability. 10 We have previously reported the synthesis of a demethoxy 9-aza-analogue (4) of eleutherol (1a) by treatment of dihydrokynurenic acid (2) with acetic anhydride in triethylamine.…”

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confidence: 99%