Diels - Alder Reactions of 3-Furylamines in Organic and Aqueous Solvents

Lingham, Anthony R.; Hügel, Helmut; Rook, Trevor J.

doi:10.1071/ch05339

Cited by 6 publications

(4 citation statements)

References 18 publications

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“…A general method for the preparation of 3-furylamines has been developed by our group [24] and products have shown high reactivity in cycloaddition reactions with methyl acrylate. [25] This has allowed the preparation of racemic 7-oxabicyclo[2.2.1]heptanone structures and investigation into their chemical transformations has been part of ongoing studies.…”

Section: Resultsmentioning

confidence: 99%

“…[25] Cycloadditions of 9a and 9b carried out in DCM were quantitative as were heterogeneous reactions in water with the aid of ultrasonic irradiation. Furylamines containing aromatic substituents have been shown to react to completion without sonication, [25] suggesting that the sonication in this case is simply a means of suspending the furan in solution, rather than a rate-enhancing phenomenon. NMR studies on the cycloadduct of 9a prepared in DCM showed the product to exist preferentially as the oxazolidine 11.…”

Section: Resultsmentioning

confidence: 99%

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Studies Towards the Synthesis of Salvinorin A

2006

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Salvinorin A 1, a psychoactive neoclerodane diterpenoid from the Mexican sage S. divinorum, has gained interest as a selective κ-opioid receptor agonist. Non-racemic 3-furylamines 9a and 9b have been prepared from (+)-pseudoephedrine and (−)-ephedrine for application in the stereoselective synthesis of the ketone ring of 1. Diels-Alder reaction of 9b with methyl acrylate in aqueous media, followed by selective ether bridge cleavage, has allowed access to the cyclohexenone 17 with preservation of stereochemistry at C2. A model route to the lactone ring has also been achieved through a one-pot deconjugation/esterification procedure of 2-bromocrotonyl chloride 20 to the furyl alcohol 19 followed by Reformatski-mediated ring closure.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Studies Towards the Synthesis of Salvinorin A

2006

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“…reactions proceed at near ambient temperatures) and may also alter the (stereochemical) outcome of the reaction. For example, a shift is noted from the typical regime of thermodynamic control to the kinetic products with 3‐substituted amino and alkoxy furans (Scheme 5, second [50] and third [79] example), but not with Boc 2‐aminofuran 18 [80] or 3,4‐dimethoxyfuran 5 [81] . In addition, these substituents readily open up channels for subsequent irreversible reactions such as hydrolysis or dehydration, [82] a topic that will be discussed in greater detail in the coming sections.…”

Section: Kineticsmentioning

confidence: 99%

The Interplay between Kinetics and Thermodynamics in Furan Diels–Alder Chemistry for Sustainable Chemicals Production

et al. 2022

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Biomass‐derived furanic platform molecules have emerged as promising building blocks for renewable chemicals and functional materials. To this aim, the Diels–Alder (DA) cycloaddition stands out as a versatile strategy to convert these renewable resources in highly atom‐efficient ways. Despite nearly a century worth of examples of furan DA chemistry, clear structure–reactivity–stability relationships are still to be established. Detailed understanding of the intricate interplay between kinetics and thermodynamics in these very particular [4+2] cycloadditions is essential to push further development and truly expand the scope beyond the ubiquitous addend combinations of electron‐rich furans and electron‐deficient olefins. Herein, we provide pertinent examples of DA chemistry, taken from various fields, to highlight trends, establish correlations and answer open questions in the field with the aim to support future efforts in the sustainable chemicals and materials production.

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“…39 Since over 5 million tons of seafood shells are produced, which contains 15-40% chitin by weight, 40 it can be envisioned that 3A5AF will play an important role as a key biomass derived N-containing synthon (Schem 1B). Based on previous examples of furan DA reactions of substrates bearing 2-amino 41 and 3-amino substituents, 42 we enquired whether the amido group of 3A5AF allowed the direct DA reaction of this carbonyl-containing furan derivate with a model dienophile, thus bypassing orbital restriction of furfural, 2-acetyl furan (AF) or even HMF (Scheme 1C). The selected model was maleimide, being a bis-activated dienophile shown to undergo DA with a variety of furanic scaffolds.…”

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Direct Diels-Alder reaction of chitin derived 3-acetamido-5-acetylfuran

Gomes

Pereira

Ravasco

et al. 2022

Preprint

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The Diels-Alder (DA) reaction of biomass derived furans is an emerging technology for the preparation of new molecular entities and “drop-in” commodity chemicals. In this work we address the challenge of the direct use of electron-poor furanic platforms as dienes through the use of an unexplored chitin derived furan, 3-acetamido-5-acetylfuran (3A5AF). The 3-acetamido group promoted a remarkable increase in the kinetics of the DA allowing for the preparation of 7-oxanorbornenes (7-ONB) at 50 ºC. Partial hydrolysis of the enamide to hemi-acylaminals was possible upon fine tuning of the reaction conditions, disabling retro-DA processes. Finally, DA reaction of the reduced form of 3A5AF allowed quantitative formation of 7-ONB in aqueous condition after 10 minutes. Certanly these are the first steps for expanding the toolbox of chitin derived 3A5AF as diene.

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Diels - Alder Reactions of 3-Furylamines in Organic and Aqueous Solvents

Abstract: Abstract:Various 5-methyl-3-aminofurans have been shown to undergo facile DielsAlder reactions with methyl acrylate in aqueous media. Reactions proceeded with exclusive regiochemistry, and enamine cycloadducts were readily hydrolysed to afford 7-oxabicyclo[2.2.1]heptanones in high yields.

Cited by 6 publications

References 18 publications

Studies Towards the Synthesis of Salvinorin A

Studies Towards the Synthesis of Salvinorin A

The Interplay between Kinetics and Thermodynamics in Furan Diels–Alder Chemistry for Sustainable Chemicals Production

Direct Diels-Alder reaction of chitin derived 3-acetamido-5-acetylfuran

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