Brønsted acid-catalyzed stereoselective [4+3] cycloadditions of ortho-hydroxybenzyl alcohols with N,N′-cyclic azomethine imines

Mei, Guang‐Jian; Zhu, Ziqi; Zhao, Jiajia; Bian, Chen-Yu; Chen, Jie; Chen, Ruo-Wei; Shi, Feng

doi:10.1039/c6cc09775h

Cited by 81 publications

(13 citation statements)

References 74 publications

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“…In 2017, Shi reported the highly diastereoselective (4+3)-annulation between o-QMs or aza-o-QMs and N,N′cyclic azomethine ylides using 10 mol% of a phosphoric acid catalyst in PhMe at 80 °C in the presence of 5 Å MS (Scheme 5.2.8). 109 Numerous Brønsted acids were tested including AcOH, TFA, TsOH, TfOH, MsOH, HBr and HCl, but none gave the desired cycloadduct. The use of CPAs under various conditions led to only 28% ee.…”

Section: Special Topic Synthesismentioning

confidence: 99%

Recent Advances in Transition-Metal-Free (4+3)-Annulations

et al. 2021

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Abstract(4+3)-Annulations are incredibly versatile reactions which combine a 4-atom synthon and a 3-atom synthon to form both 7-membered carbocycles as well as heterocycles. We have previously reviewed transition-metal-catalyzed (4+3)-annulations. In this review, we will cover examples involving bases, NHCs, phosphines, Lewis and Brønsted acids as well as some rare examples of boronic acid catalysis and photocatalysis. In analogy to our previous review, we exclude annulations involving cyclic dienes like furan, pyrrole, cyclohexadiene or cyclopentadiene, as Chiu, Harmata, Fernándes and others have recently published reviews encompassing such substrates. We will however discuss the recent additions (2010–2020) to the literature on (4+3)-annulations involving other types of 4-atom-synthons.1 Introduction2 Bases3 Annulations Using N-Heterocyclic Carbenes3.1 N-Heterocyclic Carbenes (NHCs)3.2 N-Heterocyclic Carbenes and Base Dual-Activation4 Phosphines5 Acids5.1 Lewis Acids5.2 Brønsted Acids6 Boronic Acid Catalysis and Photocatalysis7 Conclusion

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Section: Special Topic Synthesismentioning

confidence: 99%

Recent Advances in Transition-Metal-Free (4+3)-Annulations

et al. 2021

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“…Shi and co‐workers found that in situ generated oQMs from phosphoric acid‐catalysed dehydration undergo diastereoselective [4+3] cycloaddition with cyclic azomethine imines as 1,3‐dipoles [70] . For example, oQM precursor 68 reacts with 67 using 10 mol % 69 to form cis ‐heterocycle 70 in good yield and >95:5 dr (Scheme 35).…”

Section: Dehydrative Alkylation Of Heteroatomsmentioning

confidence: 99%

“…Shi and co-workersf ound that in situ generated oQMs from phosphoric acid-catalysed dehydrationu ndergo diastereoselective [4+ +3] cycloaddition with cyclic azomethinei mines as 1,3dipoles. [70] For example, oQM precursor 68 reacts with 67 using 10 mol % 69 to form cis-heterocycle 70 in good yield and > 95:5 dr (Scheme 35). The reaction works best for phenolic oQM precursors bearing an electron-donating methoxy substituenta nd is tolerant of aryl or alkyl substituents in the benzylic position and aryl substituents within the azomethine imine component.…”

Section: Dehydrative Cànb Ond Formationmentioning

confidence: 99%

Brønsted Acid‐Catalysed Dehydrative Substitution Reactions of Alcohols

Estopiñá-Durán

Taylor

2020

Chemistry A European J

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“…The yields were slightly lower, when alkyl-substituted azomethine imines 47 were employed (R 2 = alkyl; Scheme 33). 78 Although NHC L18-catalyzed reaction of 47 and 49 with enals 110 afforded pyrazolo[1,2-a]diazepines 111 in only fair yields, the enantioselectivities were excellent, mostly above 90% ee. The reaction proceeds by an oxidative catalytic remote activation of enals 110 with O1 to generate 1,4-dipolarophile intermediates that react with 1,3-dipoles 47 and 49.…”

Section: Review Syn Thesismentioning

confidence: 99%

Copper-Catalyzed Azomethine Imine–Alkyne Cycloadditions (CuAIAC)

Grošelj

Požgan²,

Štefane³

et al. 2018

Synthesis

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Although the first example of copper-catalyzed azomethine imine–alkyne cycloaddition (CuAIAC) was published only a year after the seminal papers of Meldal and Sharpless on Cu-catalyzed azide–alkyne cycloaddition (CuAAC), the CuAIAC reaction has remained overlooked by the synthetic community for almost a decade. Since 2010, however, CuAIAC reaction started to emerge as a promising supplement to the well-known CuAAC reaction. The present review surveys primarily the literature on CuAIAC reaction since 2003. Beside this, azomethine imine–alkyne cycloadditions catalyzed by other metals, selected examples of metal-free reactions, and related [3+3] and [3+4] cycloadditions of azomethine imines are presented. All these experimental data indicate the viability of CuAIAC in organic synthesis and the applicability in ‘click’ chemistry.1 Introduction2 Reactions with Acyclic Azomethine Imines3 Reactions with C,N-Cyclic Azomethine Imines4 Reactions with N,N-Cyclic Azomethine Imines5 Reactions with C,N,N-Cyclic Azomethine Imines6 The Mechanism of the CuAIAC Reaction7 Conclusions and Outlook

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Brønsted acid-catalyzed stereoselective [4+3] cycloadditions of ortho-hydroxybenzyl alcohols with N,N′-cyclic azomethine imines

Cited by 81 publications

References 74 publications

Recent Advances in Transition-Metal-Free (4+3)-Annulations

Recent Advances in Transition-Metal-Free (4+3)-Annulations

Brønsted Acid‐Catalysed Dehydrative Substitution Reactions of Alcohols

Copper-Catalyzed Azomethine Imine–Alkyne Cycloadditions (CuAIAC)

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