Atroposelective Arene Formation by Carbene‐Catalyzed Formal [4+2] Cycloaddition

Xu, Ke; Li, Wenchang; Zhu, Shaoheng; Zhu, Tingshun

doi:10.1002/anie.201910049

Cited by 107 publications

(45 citation statements)

References 146 publications

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“…To demonstrate the synthetic applications of these biaryl compounds, which were generated from this cascade Chan‐Lam O ‐arylation/[3,3]‐rearrangement protocol, bromo‐substituted biaryl 7 k was prepared under starandard conditions as the representative compound. The protecting group could be efficiently removed in the presence of hydrazine hydrate to afford 10 (Scheme 2a), [23] which could further react with isothiocyanate to generate thiourea 11 in 82% yield (Scheme 2b) [24] . The Cu(OAc) 2 ‐mediated Chan‐Lam coupling reaction of 7 k with phenylboronic acid proceed smoothly to give the O ‐arylated product 12 in excellent yield (Scheme 2c) [4] .…”

Section: Methodsmentioning

confidence: 99%

Cascade Chan‐Lam C−O Coupling/[3,3]‐Rearrangement of Arylhydroxylamines with Arylboronic Acids Toward NOBIN Analogues

et al. 2021

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Herein, we developed a copper‐mediated Chan‐Lam type O‐arylation of arylhydroxylamines with arylboronic acids to generate transient N,O‐diarylhydroxylamines that could rapidly undergo cascade [3,3]‐sigmatropic rearrangement and rearomatization to afford NOBIN (2‐amino‐2′‐hydroxy‐1,1′‐binaphthyl) analogues under mild conditions. The newly synthesized racemic biaryl products can be further resolved by a chiral DMAP‐catalyzed O‐acylation/kinetic resolution protocol.

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Section: Methodsmentioning

confidence: 99%

Cascade Chan‐Lam C−O Coupling/[3,3]‐Rearrangement of Arylhydroxylamines with Arylboronic Acids Toward NOBIN Analogues

et al. 2021

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“…In 2019, Zhu and co-workers described an atroposelective arene formation reaction by NHC-catalyzed intermolecular (4 + 2) benzannulation, building axially chiral molecules with multi-substituted arenes (Scheme 40). [68] Condition optimization showed that the N-Mes substituent was necessary for the reactivity of catalyst and the loading of NHC pre-catalyst could also be reduced to even 2 mol%. Interestingly, simply switching the phenyl substituent in the aldehyde substrates (R 1 ) and ketone substrates (R 3 ) successfully led to both enantiomers under the same reaction conditions.…”

Section: N-heterocyclic Carbene (Nhc)-catalyzed Benzannulation Reactionsmentioning

confidence: 99%

Recent Advances in Organocatalyst‐Mediated Benzannulation Reactions

2020

Adv Synth Catal

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Aromatic compounds are omnipresent in organic chemistry, which are the broadest skeletons of bioactive molecules, medicines, and materials. Due to their importance, conventional methods to assemble aromatic rings have attracted considerable attention. The direct formation of benzene cores from readily available acyclic precursors offers a highly versatile and superior approach to prepare both small organic molecules and sophisticated natural products. Recently, organocatalyst-mediated annulation reaction, including phosphine-, tertiary amine-, secondary amine-, primary amine-, and NHC-mediated benzannulation reactions, is considered as an efficient method to access multi-substituted arenes. In this review, we will emphasize the selected examples of organocatalyst-mediated benzannulation reactions of available acyclic precursors for the construction of diverse aromatics.

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“…The quaternary all-carbon centers adjacent to arenes have remained difficult to install using conventional synthetic strategies. Recently, Chi, Chai and we 61 Recently, our group 62 developed an organocatalytic intermolecular benzannulation strategy to prepare polysubstituted axially chiral biaryls (Scheme 41). In the presence of NHC catalyst C30, DABCO and an oxidant, ,,,-unsaturated aldehydes 149 and benzyl ketones 150 underwent an enantioselective [4+2] cycloaddition to generate the corresponding atropisomeric arenes 151 in good yields (up to 95% yield) and excellent enantioselectivities (90-98% ee).…”

Section: Short Review Synthesismentioning

confidence: 99%

Recent Progress towards Organocatalyzed Asymmetric (Hetero)Arene Formation

Xu¹,

Wang²,

Zhu³

2020

Synthesis

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Owing to the importance of arene moieties in organic chemistry, methods for arene construction attract great attention. Besides the traditional substitution strategy from pre-existing arenes, the straightforward formation of arene cores can also provide significant shortcuts towards a wide array of target molecules with different substitution patterns. Among direct arene formation reactions, applying environmentally benign organocatalysis to access arene moieties continues to attract increasing attention. This short review provides a brief summary of recent progress on organocatalyzed de novo (hetero)arene formation and applications in enantioselective synthesis.1 Introduction2 Arene Formation with Non-Covalent Organocatalysts2.1 Arene Formation with Acid Organocatalysts2.2 Arene Formation with Base Organocatalysts2.3 Arene Formation with Hydrogen-Bonding Organocatalysts3 Arene Formation with Covalent Organocatalysts3.1 Arene Formation with Lewis Base Organocatalysts3.1.1 Arene Formation with Secondary Amine Organocatalysts3.1.2 Arene Formation with Tertiary Amine, Tertiary Phosphine and Sulfide Organocatalysts3.1.3 Arene Formation with N-Heterocyclic Carbene Organocatalysts3.2 Arene Formation with Lewis Acid Organocatalysts4 Conclusion

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Atroposelective Arene Formation by Carbene‐Catalyzed Formal [4+2] Cycloaddition

Cited by 107 publications

References 146 publications

Cascade Chan‐Lam C−O Coupling/[3,3]‐Rearrangement of Arylhydroxylamines with Arylboronic Acids Toward NOBIN Analogues

Cascade Chan‐Lam C−O Coupling/[3,3]‐Rearrangement of Arylhydroxylamines with Arylboronic Acids Toward NOBIN Analogues

Recent Advances in Organocatalyst‐Mediated Benzannulation Reactions

Recent Progress towards Organocatalyzed Asymmetric (Hetero)Arene Formation

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