High diastereoselective synthesis of spiro-isoxazolonechromans via domino oxa-Michael/1,6-addition reactions of ortho-hydroxyphenylsubstituted para-quinone methides with unsaturated isoxazolones

Ye, Zaijun; Bai, Lijuan; Bai, Yan; Zhang, Gan; Zhou, Hui; Pan, Tao; Yu, Yu; Zhou, Jing

doi:10.1016/j.tet.2018.12.064

Cited by 26 publications

(12 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This protocol (Scheme 2) was further exploited to study its versatility, by subjecting various substituted aromatic aldehydes as well as heteroaromatic aldehyde to give corresponding Isoxazolones in very good yields (Table 2). Characterization studies of prepared compounds revealed parallel similarities with the reported literature data and undoubtedly supported the assigned structures [25–44] …”

Section: Resultssupporting

confidence: 81%

Silica Supported Synthesis and Quorum Quenching Ability of Isoxazolones Against Both Gram Positive and Gram Negative Bacterial Pathogens

et al. 2021

View full text Add to dashboard Cite

Isoxazolones are synthesised using easily available, economical and reusable silica (TLC grade) catalyst. High yields are obtained in aqueous reaction system with substrate tolerance without affecting the yield. This multigram scale, purification free method exhibits prospects for a large scale use in future. These compounds were screened for their potential application as quorum quenchers in pathogenic bacteria. The prepared compounds were analysed for quorum quenching (QQ) activity on Gram negative bioreporter strain Chromobacterium violaceum by inhibiting its pigment production i. e. violacein production in a concentration dependent manner. Some Isoxazolone derivatives showed very good quorum quenching activity. Moreover these derivatives also showed very good antibiofilm activity against both Gram negative (Pseudomonas aeruginosa ATCC 27853) and Gram positive (Staphylococcus aureus ATCC 6538) bacterial human pathogens through Quorum Quenching mechanism. Isoxazolones thus have enormous potential to be exploited in the medical field against bacterial infections caused by both Gram negative and Gram positive bacterial human pathogens.

show abstract

Section: Resultssupporting

confidence: 81%

Silica Supported Synthesis and Quorum Quenching Ability of Isoxazolones Against Both Gram Positive and Gram Negative Bacterial Pathogens

et al. 2021

View full text Add to dashboard Cite

show abstract

“…60 In addition, obtaining complex molecular architectures has also been of great utility in further transformations of the Michael adducts allowing, for example, an entry into versatile alkynes. 61 Although a great number of synthetic methodologies for 4-arylideneisoxazol-5-ones have been reported 23, [59][60][61][62][63][64][65][66] and they have been sometimes represented with E configuration, Z isomers are reported to be more stable. 62 X-ray crystal structures have confirmed this outcome for a few derivatives.…”

Section: L3mentioning

confidence: 99%

“…In 2019, Yu, Zhou, and co-workers 66 reported a domino oxa-Michael/1,6-addition reaction of 2-hydroxyphenylsubstituted p-quinone methide 137 and 4-alkylideneisoxazol-5-ones 136 in the presence of Et 3 N to give various new spiroisoxazolone-chromanes 138 in good yields (up to 89%) with excellent diastereoselectivities (>99:1 dr). A preliminary investigation into an asymmetric version of this reaction in the presence of quinine allowed 138 to be obtained in high yield and moderate diastereo-and enantioselectivity (Scheme 28).…”

Section: Short Review Synthesis Scheme 26 Asymmetric Michael Reactionmentioning

confidence: 99%

Asymmetric Synthesis of Isoxazol-5-ones and Isoxazolidin-5-ones

et al. 2020

View full text Add to dashboard Cite

Isoxazol-5-ones and isoxazolidin-5-ones represent two important classes of heterocycles, with several applications as bioactive compounds and as versatile building blocks for further transformations. Unlike the parent aromatic isoxazoles, the presence of one or two stereocenters in the ring renders their asymmetric construction particularly important. In this review, starting from the description of general features and differences between these two related compound families, we present an overview on the most important enantioselective synthesis strategies to access these heterocycles. Both chiral metal catalysts and organocatalysts have recently been successfully employed for this task and some of the most promising approaches will be discussed.1 Introduction2 Isoxazol-5-ones as Nucleophiles2.1 Isoxazol-5-ones as C-Nucleophiles2.2 Isoxazol-5-ones as N-Nucleophiles2.3 Isoxazol-5-ones as C-Nucleophiles in Cyclization Processes3 Asymmetric Construction of Isoxazolidin-5-ones3.1 Enantioselective α-Functionalizations of Isoxazolidin-5-ones4 Arylideneisoxazol-5-ones in Conjugated Addition5 Conclusions

show abstract

“…Finally, unsaturated isoxazolones were used as the partner in the reaction with o-hydroxyphenyl substituted p-quinone methides affording spiro-isoxazolonechromans [50]. The paper mainly describes the classical reaction and authors surmised a domino oxa-Michael/1,6-addition reactions, rather than a [4+2] cycloaddition.…”

Section: Cycloaddition Of Ortho-quinone Methidesmentioning

confidence: 99%

“…However, 4-(3,5-di-tert-butyl-4-hydroxyphenyl)-3 -methyl-2-(p-tolyl)-5 H-spiro[chromane-3,4 -isoxazol]5 -one was recovered in 82% yield with unsatisfactory diasteroselectivity and enantioselectivity (21:79 dr, 11/48% ee). Finally, unsaturated isoxazolones were used as the partner in the reaction with o-hydroxyphenyl substituted p-quinone methides affording spiro-isoxazolonechromans [50]. The paper mainly describes the classical reaction and authors surmised a domino oxa-Michael/1,6-addition reactions, rather than a [4+2] cycloaddition.…”

Section: Cycloaddition Of Ortho-quinone Methidesmentioning

confidence: 99%

Recent Advances in Organocatalyzed Asymmetric Synthesis of Benzopyran and Benzodihydropyran (Chromane) Nuclei

Dalpozzo

Mancuso

2019

Symmetry

View full text Add to dashboard Cite

Benzopyran and benzodihydropyran (chromane) nuclei are the core structure of many natural products, in particular flavonoids. Many compounds possessing this structure are nutraceuticals, pharmaceutical nutrients. Therefore, benzopyran and chromane scaffolds are important building blocks in organic synthesis and many efforts have been made to set up efficient methods for their synthesis. In particular, asymmetric methods are of great importance, being natural products, and generally chiral substances. This review aims to cover literature in the range 2017-first half of 2019.It should be noted that the oxa-Michael-Henry reaction between two molecules of nitrostyrene was not observed. Symmetry 2020, 12, x FOR PEER REVIEW 4 of 33 Scheme 2. Heterogeneous enantioselective synthesis of chromanes.Xia, Xu and co-workers performed an enantioselective, organocatalytic oxa-Michael-nitro-Michael reaction, but in this case, too, 2-hydroxynitrostyrenes reacted only with β-nitroolefins different from themselves [10]. The reaction afforded chiral chromane derivatives bearing three contiguous stereogenic centers (Scheme 3). The all-S stereochemistry was assigned by X-ray analysis. Subsequently, Andrés, Pedrosa and co-workers extended the reaction to polymer-supported squaramides [11]. Initially, they tested some 4-vinylphenyl-substituted squaramides and found that Squa2 (see Scheme 1, 5 mol%, rt, 12-72 h in dichloromethane) gave the best results (65-88% yields, 63:27 to >99:1 dr, 70-> 99% ee, 13 examples). The absolute configuration was once more (2S,3S,4S) and was established by X-ray analysis. The configuration of the minor isomer was instead established as (2S,3R,4S) by comparison of the 1 H-NMR coupling constants of the two diastereomers. Then Squa2 was co-polymerized with styrene and divinylbenzene and the experiments were repeated (65-86% yields, 58:42 to >99:1 dr, 56-74% ee). The polymer-supported catalyst was also recovered and recycled five times without affecting yields and selectivity. Finally, the enantiomers were obtained from a squaramide derived from (1R,2R)-1,2-cyclohexanediamine instead of Squa2 derived from α-amino acid. The authors attributed the opposite stereochemistry to a different assembly of the ternary complex formed by catalyst, nitroalkene and 2-hydroxynitrostyrene in the two cases. S O HN HO HO OHC Symmetry 2019, 11, 1510 5 of 31 Symmetry 2020, 12, x FOR PEER REVIEW 5 of 33 Scheme 3. Organocatalytic oxa-Michael nitro-Michael domino reaction.Another domino Michael/hemiacetalization (see also Scheme 2, eq 3) was carried out between aliphatic aldehydes and (E)-2-(2-nitrovinyl)phenols under modularly designed organocatalysts (Scheme 4) [12]. Cis-3,4-disubstituted chroman-2-ones were obtained after oxidation of the hemiacetal intermediate or chromanes after dehydroxylation. The reaction was scaled up to 0.5 mmol scale, without significant modification of yield and selectivity. The absolute stereochemistry was determined by the optical rotation of known compounds. Scheme 4. Domino reaction catalyzed by MDO o...

show abstract

High diastereoselective synthesis of spiro-isoxazolonechromans via domino oxa-Michael/1,6-addition reactions of ortho-hydroxyphenylsubstituted para-quinone methides with unsaturated isoxazolones

Cited by 26 publications

References 28 publications

Silica Supported Synthesis and Quorum Quenching Ability of Isoxazolones Against Both Gram Positive and Gram Negative Bacterial Pathogens

Silica Supported Synthesis and Quorum Quenching Ability of Isoxazolones Against Both Gram Positive and Gram Negative Bacterial Pathogens

Asymmetric Synthesis of Isoxazol-5-ones and Isoxazolidin-5-ones

Recent Advances in Organocatalyzed Asymmetric Synthesis of Benzopyran and Benzodihydropyran (Chromane) Nuclei

Contact Info

Product

Resources

About