Enantioselective Conjugate Addition of 2‐Acylimidazoles with Nitroalkenes Promoted by Chiral‐at‐Metal Rhodium(III) Complexes

Thota, Ganesh Kumar; Sun, Guodong; Deng, Tao; Li, Yang; Kang, Qiang

doi:10.1002/adsc.201701377

Cited by 14 publications

(7 citation statements)

References 68 publications

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“…[58] Recently, Kang and co-workers have reported the enantioselective conjugate addition of saturated 2-acyl-imidazoles on nitroalkenes catalyzed by chiral Lewis acid complex Λ-RhO2 (Scheme 45). [59] Scheme 39.…”

Section: Asymmetric Lewis Acid Catalysismentioning

confidence: 99%

Acyl‐Imidazoles: A Privileged Ester Surrogate for Enantioselective Synthesis

et al. 2019

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Since the first report by Evans in asymmetric Friedel-Crafts reactions, the use of acyl-imidazoles has blossomed as powerful ester/amide surrogates. The imidazole scaffold indeed displays stability and special activation features allowing both better reactivity and selectivity in traditional ester/amide functionalizations: α-(enolate chemistry), β-(conjugate additions), α,β-(cyclo-additions) or γ/δ-(vinylogous). An overview of the contemporary and growing interest in acyl-imidazoles in metal-and organo-catalyzed transformations (bio-hybrid catalytic systems will be fully described in a back-to-back Minireview) will be highlighted. Moreover, post-functionalization expediencies are also going to be discussed in this Minireview. Scheme 1. Synthesis of acyl-imidazoles by Okamoto and co-workers.Scheme 2. Synthesis of α,β-unsaturated acyl-imidazoles. . α-Alkylation of 2-naphthylmethyloxy acyl-imidazoles through PTC catalysis. NPM = 2-naphthylmethyl.Scheme 47. Chemo-and enantioselective oxidative cycloetherification of 2acyl-imidazoles with chiral quaternary ammonium salts. (please, change the chemdraw scheme 47; a new one is given) Scheme 48. Organocatalyzed enantioselective conjugate addition of aryl trifluoroborate to α,β-unsaturated 2-acyl 1-methylimidazole. 2 3 4 5 6 7 8

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Section: Asymmetric Lewis Acid Catalysismentioning

confidence: 99%

Acyl‐Imidazoles: A Privileged Ester Surrogate for Enantioselective Synthesis

et al. 2019

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“…In 2015, Wang and co‐workers described the use of α‐substituted acyl imidazoles as pre‐nucleophiles in conjugate addition to nitroalkenes catalyzed by a nickel complex generated from Ni(OAc) 2 and a chiral diamine ligand [5b] . While, Kang and co‐workers disclosed a chiral‐at‐metal rhodium complex catalyzed asymmetric conjugate addition of acyl imidazoles to nitroalkenes [5f] . It is notable that it took as low as 1 mol% metal catalysts to achieve high level of yields and enantioselectivity in Wang's and Kang's reports.…”

Section: Methodsmentioning

confidence: 99%

Conjugate Addition of α‐Substituted Acyl Imidazoles to Nitroalkenes Catalyzed by Nickel Bisoxazoline and B(C₆F₅)₃

Yin

Wang

et al. 2022

Adv Synth Catal

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A diastereoselective and enantioselective conjugate addition of α‐substituted acyl imidazole to nitroalkene catalyzed by nickel bisoxazoline complex and B(C6F5)3 has been developed. This reaction tolerated a wide range of acyl imidazoles and nitroalkenes, affording a series of conjugate adducts in yields ranging from 38% to 99% with 4:1 to 99:1 dr and 13% to 98% ee. The use of strong Lewis acid B(C6F5)3 as co‐catalyst proved vital to the success of this process. The potential scalability and utility of the current protocol are demonstrated by a reaction on a 3 mmol scale and further transformations of the product.

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“…The highly Lewis acidic chiral-at-rhodium complex 93 with a 3,5-ditrifluoromethyl phenyl group in the ligand backbone was also found to be effective for the enantioselective conjugate addition of 2-acyl imidazoles 171 to nitroalkenes 173 ( Scheme 30 ). 91 The γ-nitro ketone derivatives 174 were synthesized in good yields (up to 99%) and excellent enantioselectivities (up to >99% ee). The stereoselectivity can similarly be assigned by the Re -face attack of the in situ rhodium enolate 175 to the nitroalkene electrophile 176 .…”

Section: Chiral Lewis Acid Catalysismentioning

confidence: 99%

Recent Development of Bis-Cyclometalated Chiral-at-Iridium and Rhodium Complexes for Asymmetric Catalysis

2021

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The field of asymmetric catalysis has been developing to access synthetically efficacious chiral molecules from the last century. Although there are many sustainable ways to produce nonracemic molecules, simplified and unique methodologies are always appreciated. In the recent developments of asymmetric catalysis, chiral-at-metal Lewis acid catalysis has been recognized as an attractive strategy. The catalysts coordinatively activate a substrate while serving the sole source of chirality by virtue of its helical environment. These configurationally stable complexes were utilized in a large number of asymmetric transformations, ranging from asymmetric Lewis acid catalysis to photoredox and electrocatalysis. Here we provide a comprehensive review of the current advancements in asymmetric catalysis utilizing iridium and rhodium-based chiral-at-metal complexes as catalysts. First, the asymmetric transformations via LUMO and HOMO activation assisted by a chiral Lewis acid catalyst are reviewed. In the second part, visible-light-induced asymmetric catalysis is summarized. The asymmetric transformation via the electricity-driven method is discussed in the final section.

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Enantioselective Conjugate Addition of 2‐Acylimidazoles with Nitroalkenes Promoted by Chiral‐at‐Metal Rhodium(III) Complexes

Abstract: An enantioselective conjugate addition of 2-acylimidazoles with nitroalkenes catalyzed by chiral-at-metal rhodium(III) complex under mild reaction conditions was developed, affording versatile g-nitro ketone skeletons in good yields with excellent enantioselectivities (up to > 99% ee).

Cited by 14 publications

References 68 publications

Acyl‐Imidazoles: A Privileged Ester Surrogate for Enantioselective Synthesis

Acyl‐Imidazoles: A Privileged Ester Surrogate for Enantioselective Synthesis

Conjugate Addition of α‐Substituted Acyl Imidazoles to Nitroalkenes Catalyzed by Nickel Bisoxazoline and B(C₆F₅)₃

Recent Development of Bis-Cyclometalated Chiral-at-Iridium and Rhodium Complexes for Asymmetric Catalysis

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Enantioselective Conjugate Addition of 2‐Acylimidazoles with Nitroalkenes Promoted by Chiral‐at‐Metal Rhodium(III) Complexes

Abstract: An enantioselective conjugate addition of 2-acylimidazoles with nitroalkenes catalyzed by chiral-at-metal rhodium(III) complex under mild reaction conditions was developed, affording versatile g-nitro ketone skeletons in good yields with excellent enantioselectivities (up to > 99% ee).

Cited by 14 publications

References 68 publications

Acyl‐Imidazoles: A Privileged Ester Surrogate for Enantioselective Synthesis

Acyl‐Imidazoles: A Privileged Ester Surrogate for Enantioselective Synthesis

Conjugate Addition of α‐Substituted Acyl Imidazoles to Nitroalkenes Catalyzed by Nickel Bisoxazoline and B(C6F5)3

Recent Development of Bis-Cyclometalated Chiral-at-Iridium and Rhodium Complexes for Asymmetric Catalysis

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Conjugate Addition of α‐Substituted Acyl Imidazoles to Nitroalkenes Catalyzed by Nickel Bisoxazoline and B(C₆F₅)₃