The Quinary Catalyst–Substrate Complex Induced Construction of Spiro-Bridged or Cagelike Polyheterocyclic Compounds via a Substrate-Controlled Cascade Process

Wang, Chen; Chen, Ying-Han; Wu, Hui-Chun; Liu, Yankai

doi:10.1021/acs.orglett.9b02375

Cited by 27 publications

(10 citation statements)

References 63 publications

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“…The achievement of the novel multicatalytic strategy obtained by Xu group [32b–e] was depended on the assembly of iminium ion catalysis and anion‐binding catalysis, where a monofunctional H‐bonding donating catalyst was utilized to connect the iminium counteranion through anion binding [18a,34] . Recently, Liu and co‐workers developed an asymmetric organocatalytic cascade reaction of cyclic β ‐oxo aldehydes 55 or 56 with 2‐hydroxycinnamaldehydes 54 assisted by chiral amine Cat‐22 , bifunctional tertiary amine‐thiourea Cat‐23 , and benzoic acid to afford spiro‐bridged products 57 or cage‐like polyheterocyclic compounds 58 (Scheme 19a) [35] . In this process, the quinary catalyst‐substrate complex Int‐39 derived from the combination of asymmetric iminium ion catalyst, thiourea anion‐binding catalyst and carboxylate anion is indispensable for the construction of enantioenriched spirobridged and cage‐like polyheterocyclic compounds.…”

Section: Asymmetric Reactions Catalyzed By Multi‐organocatalystsmentioning

confidence: 99%

Recent Advances in Asymmetric Organomulticatalysis

Xiao

Shao

et al. 2020

Adv Synth Catal

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Asymmetric multi‐catalysis, designed to mimic catalytic processes in nature, is a powerful instrument to fulfil fascinating transformations. As a result, this area of research has attracted considerable interests within chemistry communities. Although there are numerous reviews involving multi‐catalysis, reviews describing asymmetric organomulticatalysis remain rare. Taking into consideration that organocatalysts possess the superiorities of effortless availability, inexpensiveness, hypotoxicity, facile handling and hyposensitivity to moisture and oxygen, they have definite advantage in their own distinct modes of activation when utilized in multi‐catalytic reactions. Organomulticatalysis refers to the synthetic strategies of modular combination of organo‐catalyzed reactions into one synthetic operation with minimum workup or change in conditions. It is apparent that a variety reports utilizing the concept of enantioselective organomulticatalysis have substantially surfaced in the past few years. Hence, it is indispensable to succinctly present all such reports by means of disclosing the mechanistic analysis, as well as the challenges and issues associated in the development of the asymmetric catalytic system. Additionally, this review will introduce some of the unsettled conundrums and possible innovations in this field.

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Section: Asymmetric Reactions Catalyzed By Multi‐organocatalystsmentioning

confidence: 99%

Recent Advances in Asymmetric Organomulticatalysis

Xiao

Shao

et al. 2020

Adv Synth Catal

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“…To increase the significance of the reaction some chemical transformations of these compounds were successfully carried out. Then the reaction was extended to cyclic β-oxoaldehydes [29]. A bifunctional tertiary aminethiourea catalyst was employed to activate the oxoaldehyde toward the attack to the iminium ion from 2-hydroxycinnamaldehyde (Scheme 18).…”

Section: Scheme 13 Synthesis Of Chiral Chromane-containing Polyhetermentioning

confidence: 99%

“…One example is the enantioselective synthesis of 4-aryl-3,4-dihydrocoumarins by reaction of phenols with α,βunsaturated arylaldehydes, catalyzed by NHC and with 3,3′,5,5′-tetra-t-butyldiphenoquinone as the oxidant (Scheme 38) [54]. In contrast to the reaction described in Scheme 20 [29], simple electron- The reaction of chroman-2-ols and (E)-4-nitrobut-3-en-1-ynes in the presence of the Jørgensen-Hayashi catalyst (J-Ha) led to an enantioenriched lactol, which can undergo ring-closure in the presence of Hg(OTf) 2 [52,53]. Then the tricyclic compound was submitted to the addition of some nucleophiles, and N-alkylindoles were found to be the most efficient (Scheme 37).…”

Section: Miscellaneousmentioning

confidence: 99%

“…One example is the enantioselective synthesis of 4-aryl-3,4-dihydrocoumarins by reaction of phenols with α,βunsaturated arylaldehydes, catalyzed by NHC and with 3,3′,5,5′-tetra-t-butyldiphenoquinone as the oxidant (Scheme 38) [54]. In contrast to the reaction described in Scheme 20 [29], simple electron- Ethanol did not react, phenylmethanethiol opened the cycle, triethylsilane reduced the double bond and N-bromosuccinimide (NBS) in methanol gave the addition of BrOMe. The absolute configuration of products was determined by X-ray analysis.…”

Section: Miscellaneousmentioning

confidence: 99%

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

Dalpozzo

Mancuso

2019

Symmetry

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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...

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“…A combination of privileged frameworks is a powerful way to improve molecular diversity and thus discover novel biological properties . Therefore, efficient construction of polyheterocyclic skeletons from readily available starting materials in a minimum number of steps is a highly desired but challenging theme in organic synthesis. − One of the ways to fulfill this goal is the development and use of domino processes, which allow the sequential construction of several bonds by a single-step manipulation. − During our ongoing investigation of domino reactions of thioaurones, − we are interested in the effect on the reaction mode of replacing a substrate oxygen atom with a sulfur atom. Due to the different atomic properties, the sulfur atom may play a different role in controlling the reactivity/selectivity as compared to the oxygen atom.…”

Section: Introductionmentioning

confidence: 99%

Construction of [6-5-5-6-6] Pentacyclic Skeleton via a Phosphine-Catalyzed Domino Reaction and Mechanism Study

Zhang

et al. 2020

J. Org. Chem.

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A novel phosphine-promoted domino reaction between thioaurone or aurone derivatives and MBH carbonate is described. A wide range of [6-5-5-6-6] pentacyclic compounds was prepared efficiently. Interestingly, the stereoselectivity was affected by the sulfur or oxygen atom in the substrates. Moreover, the reaction mechanism was explored by density functional calculations, which identified the 1,4-hydrogen-shift step to be the selectivity-determining step.

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The Quinary Catalyst–Substrate Complex Induced Construction of Spiro-Bridged or Cagelike Polyheterocyclic Compounds via a Substrate-Controlled Cascade Process

Cited by 27 publications

References 63 publications

Recent Advances in Asymmetric Organomulticatalysis

Recent Advances in Asymmetric Organomulticatalysis

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

Construction of [6-5-5-6-6] Pentacyclic Skeleton via a Phosphine-Catalyzed Domino Reaction and Mechanism Study

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