Organocatalytic Diversity-Oriented Asymmetric Synthesis of Tricyclic Chroman Derivatives

Geng, Zhi‐Cong; Zhang, Shao‐Yun; Li, Nai‐Kai; Li, Ning; Chen, Jian; Li, Haiyan; Wang, Xingwang

doi:10.1021/jo501560m

Cited by 54 publications

(17 citation statements)

References 74 publications

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“…Similar tricyclic benzo[ c ]chromene derivatives have also been synthesized by Wang and co‐workers using a chemoselective organocatalytic domino reaction involving the substrates 42 and 150 (Scheme ) . By adjusting the ratio of the reactants ( 42 and 150 ) and the reaction temperature, either 6a,9,10,10a‐tetrahydro‐6 H ‐benzo[ c ]chromenes 151 or 4a,10b‐dihydro‐4 H ,5 H ‐pyrano[3,4‐ c ]chromenes 152 could be obtained in high yields and excellent stereoselectivities.…”

Section: Primary and Secondary Amine Catalystsmentioning

confidence: 96%

“…By adjusting the ratio of the reactants ( 42 and 150 ) and the reaction temperature, either 6a,9,10,10a‐tetrahydro‐6 H ‐benzo[ c ]chromenes 151 or 4a,10b‐dihydro‐4 H ,5 H ‐pyrano[3,4‐ c ]chromenes 152 could be obtained in high yields and excellent stereoselectivities. It was believed that, at a lower ratio of 42 / 150 and a lower temperature (−5 °C), ( S )‐ 45 catalyzed a domino Michael/inverse‐electron‐demand hetero‐Diels–Alder reaction to yield the products 152 . However, at a higher loading of 42 and 30 °C, the initially formed 152 underwent further domino Michael/aldol condensation reaction with the excessive 42 to yield the products 151 .…”

Section: Primary and Secondary Amine Catalystsmentioning

confidence: 99%

“…However, at a higher loading of 42 and 30 °C, the initially formed 152 underwent further domino Michael/aldol condensation reaction with the excessive 42 to yield the products 151 . Taking advantage of these features of the reaction, the authors were able to introduce a different β‐aryl enal ( 42′ ) into the reaction mixture after the formation of 152 to obtain the tricyclic chromene derivatives 151′ in high yields and excellent stereoselectivities (Scheme ) …”

Section: Primary and Secondary Amine Catalystsmentioning

confidence: 99%

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Recent Progress in Organocatalytic Asymmetric Domino Transformations

2017

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Sustainability in chemical synthesis is a major aspect of the current synthetic endeavors and, therefore,m imicking the biological process in the laboratory nowadays has the highest priority.T owards achieving this goal, designingorganic reactions in domino mode rathert han the multistep synthetic pathways andu sing organocatalysisi nstead of metal catalysis have received al ot of attention due to the inherenta dvantageso ft hese processes in terms of synthetic efficiencya nd sustainability.A saresult, the field of asymmetric organocatalytic domino reactions has witnessed tremendous progress in recent years.T his review attempts to summarize the latest developments in asymmetric organocatalyzed domino reactions since 2012, with the emphasis on the catalysts andr eactionm odes.D iscussions on the reactionm echanismsa nd the applications of the developed domino reactionm ethodsi nt he synthesis of biologically active molecules and natural products are also includedwhen appropriate.

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Section: Primary and Secondary Amine Catalystsmentioning

confidence: 96%

Section: Primary and Secondary Amine Catalystsmentioning

confidence: 99%

Section: Primary and Secondary Amine Catalystsmentioning

confidence: 99%

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Recent Progress in Organocatalytic Asymmetric Domino Transformations

2017

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“…In 2014, two types of tricyclic flavane derivatives were respectively synthesized by Wang's group . There they developed the tandem oxo‐Michael‐IED/HDA and oxo‐Michael‐IED/HAD (inverse‐electron‐demand hetero‐Diels‐Alder)‐Michael‐Aldol condensation transformations between ( E )‐2‐hydroxyaryl‐2‐oxobut‐3‐enoate derivatives 78 and enals 79 in the presence of 4 a as organocatalyst.…”

Section: Asymmetric Synthesis Of Flavanesmentioning

confidence: 99%

Catalytic Asymmetric Syntheses of 2‐Aryl Chromenes

2019

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Chiral chromene motifs are important heterocycles in numerous natural products and bioactive molecules. Among them, flavenes, flavanes, and flavanones, which consist of the 2-aryl-chromene skeleton are observed most frequently. As subgroups of flavonoids, they often occur in various plants and show many biological activities, such as antitumor, antioxidant, antibacterial, anti-inflammatory, and anticoagulant properties. This Minireview summarizes recent reports on catalytic asymmetric synthesis of flavenes, flavanes, and flavanones. derivatives 1, giving the adduct 6. The subsequent intramolecular adol reaction and dehydration providing the desired product 3 (Scheme 2).Almost the same time, professor Córdova and coworkers presented the same domino reaction between 1 a and 2 catalyzed by 4 a, providing a series of 2H-flavenes in high yields and with 83-98% ees (Scheme 3). [5] Notably, by using 2nitrobenzoic acid as an additive, product 3 a could be obtained with 37% yield and 88% ee, comparing to 10% yield and 9% ee when adding no additives. More significantly, another additive, 4 Å molecular sieves, promoted the reaction significantly, increasing the product yield from 37% to 81% with no enantioselectivity erosion. The authors believed that the addition of an organic acid accelerated the adol condensation by activating the benzaldehyde. Also, the organic acid could stabilized the iminium intermediate, facilitating the oxa-Michael addition. The product 7 could be observed by NMR analysis, which gave an obvious evidence to the proposed reaction pathway (Scheme 2).By applying the similar approach, Wang and coworkers developed the asymmetric reaction of 1 and 2 catalyzed by organocatalyst 4 b. [6] Different from Córdova's condition, Wang found that Cl(CH 2 ) 2 Cl was the best solvent to provide the highest enantioselectivity. Lowering the reaction temperature improved ee with prolonged time for completion. The reaction had a broad scope and the functionalized 2H-flavenes were synthesized respectively high yields (53-98%) and with good to excellent levels of enantioselectivities (75-99% ee). However, the electronic nature of the α,β-unsaturated aldehydes 2 had a remarkable effect on the reactivities and ees that 2 bearing electron-withdrawing groups, such as nitro group, generally Scheme 2. Proposed mechanism of the organocatalytic asymmetric oxa-Michael addition/intramolecular adol reaction/dehydration cascade. Scheme 3. Direct organocatalytic asymmetric domino oxa-Michael/aldol condensations between 1 a and α, β-unsaturated aldehydes 2.

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“…In 2014, Wang group reported the organocatalytic tandem oxo ‐Michael‐IEDHDA reactions between ( E )‐2‐hydroxyaryl‐2‐oxobut‐3‐enoates 70 and enals 71 (Scheme ) . With ( S )‐diphenylprolinol trimethylsilyl ether 73 as the organocatalyst and enals 71 as the precursors of dienophiles, a variety of tricyclic chroman derivatives 72 were delivered in 75–93 % yields with 98‐>99 % ee.…”

Section: Catalytic Asymmetric Iedhda Reactions Of Carbonyl Compoundsmentioning

confidence: 99%

Catalytic Asymmetric Inverse‐Electron‐Demand Hetero‐Diels−Alder Reactions

Xie

Lin

Feng

2017

The Chemical Record

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In this review, the recent developments in catalytic asymmetric inverse-electron-demand hetero-Diels-Alder reaction, which is recognized as one of the most powerful routes to construct highly functionalized and enantioenriched six-membered heterocycles, are described. The article is organized on the basis of different kinds of electron-deficient heterodienes, including α,β-unsaturated ketones/aldehydes, o-benzoquinones, α,β-unsaturated imines, N-aryl imines, o-benzoqinone imides, and other aza-olefins.

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Organocatalytic Diversity-Oriented Asymmetric Synthesis of Tricyclic Chroman Derivatives

Cited by 54 publications

References 74 publications

Recent Progress in Organocatalytic Asymmetric Domino Transformations

Recent Progress in Organocatalytic Asymmetric Domino Transformations

Catalytic Asymmetric Syntheses of 2‐Aryl Chromenes

Catalytic Asymmetric Inverse‐Electron‐Demand Hetero‐Diels−Alder Reactions

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