Organocatalyzed Dearomative Cycloaddition of 2-Nitrobenzofurans and Isatin-Derived Morita–Baylis–Hillman Carbonates: Highly Stereoselective Construction of Cyclopenta[<i>b</i>]benzofuran Scaffolds

Zhao, Jian‐Qiang; Yang, Lei; Zhou, Xiao‐Jian; You, Yong; Wang, Zhen-Hua; Zhou, Ming‐Qiang; Zhang, Xiaomei; Xu, Xiao‐Ying; Yuan, Wei‐Cheng

doi:10.1021/acs.orglett.8b03786

Cited by 78 publications

(31 citation statements)

References 92 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For such transforma-tions, the mechanism is generally accepted, when, in the first stage, the catalyst 267, the tertiary amine NR 3 nitrobenzofuran 266 (R 4 = 3-CH 3 ) does not enter into this reaction. [266] Highly diastereoselective reactions for the production of spiro-fused heterocycles were found. These syntheses, depending on the nature of the amine base used as the organocatalyst, pass as [3 + 2] or [2 + 1] cycloaddition to afford cyclopentenyl-bis-spirooxindoles 269 or cyclopropyl-spirooxindoles 270.…”

Section: Using the [3 + 2] Annulation Reaction Of Morita-baylis-hillmmentioning

confidence: 99%

Advances in the Synthesis of Benzo‐Fused Spiro Nitrogen Heterocycles: New Approaches and Modification of Old Strategies

Гатауллин

2020

Helvetica Chimica Acta

View full text Add to dashboard Cite

The review covers the results of studies published in the literature on the synthesis of spiro-linked heterocycles of the indole, quinoline, benzoxazine, benzothiazine, indenoquinoxaline, pyridopyrimidine, and acridine series. Possible approaches to the synthesis of spirocycles through a sequence of well-known Knoevenagel, Michael reactions, deamination cyclization of 1,2-dicarbonyl, CH-acid compounds, direct cycloaddition of activated olefins to isatins, 3-alkylideneindoles, 2-oxindoles, in situ generated azomethine ylides, indenoquinoxalines are analyzed. Attention is drawn to approaches to the preparation of spiro-fused compounds using reactions of intra-and intermolecular dearomatization of indoles. Recent advances in the synthesis of spiro-linked benzo heterocycles from derivatives of 2-olefin substituted anilines are summarized. The examples of the synthesis of spiro-fused heterocycles by means of metal complexes catalyzed decomposition of diazo compounds are given. Some syntheses of biologically active representatives are shown, as well as the use of transformations of spiroheterocycles in the preparation of other heterocycles.

show abstract

Section: Using the [3 + 2] Annulation Reaction Of Morita-baylis-hillmmentioning

confidence: 99%

Advances in the Synthesis of Benzo‐Fused Spiro Nitrogen Heterocycles: New Approaches and Modification of Old Strategies

Гатауллин

2020

Helvetica Chimica Acta

View full text Add to dashboard Cite

show abstract

“…Based on this strategy, our group disclosed a dearomative [3+2] annulation reaction of 3‐nitro‐7‐azaindole 49 with MBH carbonate 2 in the presence of a chiral DMAP‐type Lewis base catalyst C14 , delivering a polycyclic spirooxindole 50 possessing a fused azaindoline with modest stereoselectivity (Scheme b) . Very recently, this protocol was further developed by Yuan and co‐workers with 2‐nitrobenzofurans 51 (Scheme c) . By using a modified β‐ICD derivative C6 , asymmetric dearomative [3+2] annulations smoothly gave cyclopenta[ b ]benzofuran derivatives 52 with three contiguous stereocenters in excellent enantioselectivities.…”

Section: Annulations Via Allylic Ylidesmentioning

confidence: 99%

Transformations of Modified Morita‐Baylis‐Hillman Adducts from Isatins Catalyzed by Lewis Bases

Chen

et al. 2019

The Chemical Record

102

View full text Add to dashboard Cite

The development of synthetic protocols to access architectures with broad structural and functional diversity from readily available starting materials is very attractive in both organic and medicinal chemistry fields. Toward this objective, the multifunctional isatin‐derived Morita‐Baylis‐Hillman (MBH) adducts provide opportunities to construct a variety of complex scaffolds containing a “privileged” oxindole motif through several catalytic pathways. By forming the ammonium or phosphonium salts with Lewis bases, isatin‐derived MBH adducts can undergo allylic substitutions with a range of nucleophiles, usually in a SN2′‐SN2′ pattern. Besides, assisted by Brønsted bases, the corresponding onium salts can be converted into the allylic ylide intermediates, which can undergo various annulation reactions or even 1,3‐difunctionalizations. Moreover, recent cooperative catalysis of Lewis bases and transition metal complexes further puts forward the application of isatin‐derived MBH adducts. This tutorial review covers the significant transformations of isatin‐derived MBH adducts, mostly in an asymmetric version, catalyzed by various Lewis bases over the past decade.

show abstract

“…First, a variety of 2‐nitrobenzofurans can be readily prepared from the corresponding salicylaldehydes . Second, 2‐nitrobenzofurans have been used to synthesize benzofuran‐ or dihydrobenzofuran‐fused compounds. To our knowledge, there is only one example that four dibenzofuran derivatives are obtained by Diels‐Alder reactions of 2‐nitrobenzofuran with the substituted dienes at high reaction temperature (Scheme B, eq.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Dibenzofurans Derivatives via Benzannulation of 2‐Nitrobenzofurans and Alkylidene Malononitriles

Cao

Chen

et al. 2020

Asian J Org Chem

View full text Add to dashboard Cite

Although various methods for the preparation of dibenzofurans are available, an efficient, general synthesis of dibenzofurans from benzofurans remains an unsolved problem. Herein, we provide the first benzannulation of readily prepared 2-nitrobenzofurans with alkylidene malononitriles. This methodology enables facile assembly of a wide variety of highly functionalized dibenzofurans in moderate to excellent yields under metal-free conditions. Gram-scale synthesis and further elaborations of the product were succesfully performed, demonstrating synthetic utility of this method.

show abstract

Organocatalyzed Dearomative Cycloaddition of 2-Nitrobenzofurans and Isatin-Derived Morita–Baylis–Hillman Carbonates: Highly Stereoselective Construction of Cyclopenta[b]benzofuran Scaffolds

Cited by 78 publications

References 92 publications

Advances in the Synthesis of Benzo‐Fused Spiro Nitrogen Heterocycles: New Approaches and Modification of Old Strategies

Advances in the Synthesis of Benzo‐Fused Spiro Nitrogen Heterocycles: New Approaches and Modification of Old Strategies

Transformations of Modified Morita‐Baylis‐Hillman Adducts from Isatins Catalyzed by Lewis Bases

Synthesis of Dibenzofurans Derivatives via Benzannulation of 2‐Nitrobenzofurans and Alkylidene Malononitriles

Contact Info

Product

Resources

About