Stereospecific Synthesis of Fluorinated Pyrazolidinones and Isoxazolidines via a Catalyst‐Free 1,3‐Dipolar Cycloaddition of β‐Fluoroalkylated α,β‐Unsaturated 2‐Pyridylsulfones

Kou, Ying‐Da; Zhao, Zhen‐Ni; Yang, Xing; Kalita, Subarna Jyoti; Chen, Xuejian; Xie, Zhipeng; Zhao, Yan; Huang, Yiyong

doi:10.1002/ajoc.201800435

Cited by 9 publications

(1 citation statement)

References 64 publications

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“…In 2014, the group of Huang reported a catalyst‐free 1,3‐dipolar cycloaddition between the azomethine imines 212 and α,β‐unsaturated 2‐pyridylsulfones 211 to prepare various fluoroalkylated N,N′ ‐bicyclic pyrazolidinones 213 in moderate to excellent yields (42–98%) and high diastereoselectivities (up to 98 : 2 dr) (Scheme 55). [74] Accroding to the DFT (density functional theory) calculations, the Gibbs free energy change value of the exo‐selection pathway was lower than that of endo, so provided the exo‐adducts as the mainly configuration.…”

Section: Synthesis Of Chiral Sulfones By Asymmetric Cycloadditionmentioning

confidence: 99%

Advances in Synthesis of Enantioenriched Chiral Sulfones by Enantioselective Conjugate Addition Reactions

Liang

Shen

2021

Asian J Org Chem

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Chiral sulfones, a class of organic compounds with broad application prospects in organic synthesis and pharmaceutical chemistry, are an important part of building bioactive molecules or functional materials. In this paper, the advances and the state of synthesizing chiral sulfones by addition reactions are reviewed. The methods described in the manuscript are classified according to the types of reaction. Moreover, each chapter is arranged in chronological order.

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Section: Synthesis Of Chiral Sulfones By Asymmetric Cycloadditionmentioning

confidence: 99%

Advances in Synthesis of Enantioenriched Chiral Sulfones by Enantioselective Conjugate Addition Reactions

Liang

Shen

2021

Asian J Org Chem

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[3 + 2] Cycloadditions of Azomethine Imines

Grošelj

Svete

2020

Organic Reactions

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In spite of their late discovery in the middle of 20 th century, the importance of azomethine imines and their [3+2] cycloaddition reactions has grown constantly throughout the decades. Today, [3+2] cycloadditions of azomethine imines have become indispensable in the preparation of pyrazole derivatives with all degrees of saturation. The structural diversity of azomethine imines is wide and comprises acyclic, C , N ‐cyclic, N , N ‐cyclic, and C , N , N ‐cyclic 1,3‐dipoles. Although electron‐deficient dipolarophiles are preferred, electron‐rich dipolarophiles, such as enol ethers and enamines, are also commonly used in these reactions. Compared to cyclocondensation methods and [3+2] cycloadditions with diazoalkanes and nitrile imines, [3+2] cycloadditions with azomethine imines provide access to a greater diversity of pyrazole derivatives with all degrees of saturation. As with other 1,3‐dipolar cycloadditions, a concerted and nearly synchronous mechanism has been proposed for most [3+2] cycloadditions of azomethine imines, although a stepwise mechanism may be viable in some cases. Several examples of asymmetric [3+2] cycloadditions of azomethine imines that afford non‐racemic cycloadducts with high enantioselectivity have been reported. These asymmetric cycloadditions are performed with various types of transition metal catalysts and organocatalysts, and indicate their potential for the asymmetric synthesis of saturated pyrazole derivatives. Finally, many examples of copper‐catalyzed and thermal, strain‐promoted [3+2] cycloadditions of azomethine imines (in particular sydnones) clearly indicate wide applicability of these reactions in bioconjugation, fluorescent labelling, materials functionalization, and other applications outside the realm of pure organic synthesis.

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1,3‐Dipolar Cycloadditions of β‐Fluoroalkyl Vinylsulfones and Nitrile Oxides for Fluoroalkylated Isoxazolines and Isoxazoles

Huang

Kou

et al. 2019

Asian J Org Chem

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The 1,3‐dipolar cycloadditions of β‐fluoroalkyl vinylsulfones and nitrile oxides to deliver 5‐fluoroalkyl‐3‐substituted 2‐isoxazolines has been established under mild conditions in up to 85% yield with excellent regio‐ and diastereoselectivities (all d.r. >99 : 1), and thus facilitated rapid access to 5‐fluoroalkyl‐3‐Ph‐2‐isoxazoles by DBU‐mediated elimination of the pyridyl sulfone group.

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Stereospecific Synthesis of Fluorinated Pyrazolidinones and Isoxazolidines via a Catalyst‐Free 1,3‐Dipolar Cycloaddition of β‐Fluoroalkylated α,β‐Unsaturated 2‐Pyridylsulfones

Cited by 9 publications

References 64 publications

Advances in Synthesis of Enantioenriched Chiral Sulfones by Enantioselective Conjugate Addition Reactions

Advances in Synthesis of Enantioenriched Chiral Sulfones by Enantioselective Conjugate Addition Reactions

[3 + 2] Cycloadditions of Azomethine Imines

1,3‐Dipolar Cycloadditions of β‐Fluoroalkyl Vinylsulfones and Nitrile Oxides for Fluoroalkylated Isoxazolines and Isoxazoles

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