Diastereo‐ and Enantioselective Conjugate Addition of 3‐Chlorooxindoles to Nitroalkenes Catalyzed by Binaphthyl‐modified Organocatalyst

Jeong, Hyun Jung; Kwon, Soo Hyun; Kim, Dae Young

doi:10.1002/bkcs.10264

Cited by 13 publications

(2 citation statements)

References 59 publications

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“…The asymmetric Michael addition reaction of 3-alkyloxindoles [ 149 ] or 3-chlorooxindoles [ 150 ] to nitroalkenes has been explored recently using as organocatalysts the guanidine 137 and the squaramide 138 , respectively. The reaction conditions, yields and stereoselectivities of the corresponding adducts are shown in Figure 19 .…”

Section: Carbon Nucleophilesmentioning

confidence: 99%

Recent Advances in Asymmetric Organocatalyzed Conjugate Additions to Nitroalkenes

et al. 2017

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The asymmetric conjugate addition of carbon and heteroatom nucleophiles to nitroalkenes is a very interesting tool for the construction of highly functionalized synthetic building blocks. Thanks to the rapid development of asymmetric organocatalysis, significant progress has been made during the last years in achieving efficiently this process, concerning chiral organocatalysts, substrates and reaction conditions. This review surveys the advances in asymmetric organocatalytic conjugate addition reactions to α,β-unsaturated nitroalkenes developed between 2013 and early 2017.

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Section: Carbon Nucleophilesmentioning

confidence: 99%

Recent Advances in Asymmetric Organocatalyzed Conjugate Additions to Nitroalkenes

et al. 2017

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“…The chiral halogenated quaternary center at the C3-position plays a crucial role in determining the stereochemical properties and biological activities of these molecules . Catalytic enantioselective methods have been developed to introduce fluoro atoms selectively at the C3-position to construct 3-substituted 3-fluorooxindoles with high yields and excellent enantioselectivities, which have been largely reported. − However, the asymmetric synthesis of corresponding 3-tetrasubstituted oxindoles containing chloro stereogenic centers is relatively less explored (Scheme a,b). , Slow progress in the enantioselective synthesis of 3-substituted 3-chlorooxindole is attributed to a number of factors. First, the use of strong and reactive chlorinating agents such as N -chlorosuccinimide could pose challenges when achieving catalysis with nonselective background reactions.…”

Section: Introductionmentioning

confidence: 99%

Construction of Enantioenriched Quaternary C–Cl Oxindoles through Palladium-Catalyzed Asymmetric Allylic Substitution with Chloroenolates

Huang,

Yang,

Gao

et al. 2023

J. Org. Chem.

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A palladium-catalyzed asymmetric chloroenolate allylation with vinyl benzoxazinanones under mild reaction conditions has been developed, affording a series of optically active 3,3-disubstituted oxindoles exhibiting a chloro-group and a linear aryl amino side chain in good yields with up to 96% ee. Versatile functional group tolerance on the benzene ring has been demonstrated, and the utility of this method was probed by a scale-up synthesis and highlighted by product derivatizations.

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Diastereo‐ and Enantioselective Conjugate Addition of α‐Substituted Cyanoacetates to Maleimides Catalyzed by Binaphthyl‐based Thiourea

Kang

Kim

2015

Bulletin Korean Chem Soc

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The Michael addition reaction is widely recognized as one of the most efficient and powerful methods for the C-C bonds formation in organic synthesis.1 To date, various asymmetric Michael addition reactions have been developed.2 Chiral α-cyanoacetates bearing a quaternary stereogenic center are an important class of substrates that serve as precursors of the highly functionalized chiral compounds such as amino acids and amino alcohols with simple functional group transformation.3 Recently, organocatalytic enantioselective conjugate addition reactions of α-substituted cyanoacetates with various Michael acceptors have been reported. 4 Until now, there are a few reports for the catalytic conjugate addition of α-substituted cyanoacetates to maleimides using organocatalysts.5 Although these methods are satisfyingly efficient in some extent, new organocatalytic conjugate addition of α-substituted cyanoacetates to maleimides is highly desired.As part of our research program related to the development of synthetic methods for the enantioselective construction of stereogenic carbon centers, 6 we recently reported the asymmetric Michael addition reactions of active methines using chiral catalysts.7 Herein, we wish to describe the conjugate addition of α-substituted cyanoacetates with maleimide promoted by binaphthyl-based organocatalysts.To determine suitable reaction conditions for the catalytic enantioselective Michael addition of α-substituted cyanoacetates, we initially investigated the reactions with N-phenylmaleimide (2a) in the presence of 10 mol % binaphthyl-based organocatalysts I-IV bearing both central and axial chiral elements ( Figure. 1). As shown in Table 1, binaphthyl-based (thio)urea catalysts I-III effectively promoted the reaction in toluene with high enantioselectivities (entries 1-3, Table 1). Replacement of urea function with squaramide (catalyst IV) slightly decreased the enantioselectivity (entry 4, - Table 1), and the highest enantioselectivities obtained with the binaphthyl-based thiourea catalyst II. For further improvement of selectivity, different solvents were then tested in the presence of 10 mol % of catalyst II. Aprotic solvents such as toluene, benzene, diethyl ether, THF, and dichloromethane were well tolerated in this Michael addition without a significant decrease of enantioselectivities (76-96% enantiomeric excesses [ee], entries 2 and 5-9, Table 1). Among the solvents probed, toluene provided the best results (79% yield, 9:1 dr, 96% ee, entry 2, Table 1). The present catalytic system tolerates catalyst loading down to 5 mol %, and both the yields and enantioselectivities were retained (entries 4 and 10-11, Table 1).With the optimized conditions in hand, we proceeded to investigate the scope of the enantioselective conjugate addition of various α-substituted cyanoacetates 1 and N-phenylmaleimide (2a) in the presence of 5 mol % of binaphthylbased thiourea-tertiary amine catalyst II in toluene at room temperature. The results of conjugate addition reaction are summarized in Table 2. A ra...

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Diastereo‐ and Enantioselective Conjugate Addition of 3‐Chlorooxindoles to Nitroalkenes Catalyzed by Binaphthyl‐modified Organocatalyst

Cited by 13 publications

References 59 publications

Recent Advances in Asymmetric Organocatalyzed Conjugate Additions to Nitroalkenes

Recent Advances in Asymmetric Organocatalyzed Conjugate Additions to Nitroalkenes

Construction of Enantioenriched Quaternary C–Cl Oxindoles through Palladium-Catalyzed Asymmetric Allylic Substitution with Chloroenolates

Diastereo‐ and Enantioselective Conjugate Addition of α‐Substituted Cyanoacetates to Maleimides Catalyzed by Binaphthyl‐based Thiourea

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