Asymmetric aza‐Friedel–Crafts Reaction of Cyclic Ketimines with 5‐Aminopyrazole Derivatives: Expedient Access to Pyrazole‐Based C2‐quaternary Indolin‐3‐Ones

A chiral phosphoric acid‐catalyzed enantioselective aza‐Friedel–Crafts reaction of 5‐aminopyrazole derivatives with cyclic ketimines attached to a neutral functional group is reported. This protocol allows the formation of pyrazole‐based C2‐quaternary indolin‐3‐ones with high enantioselectivities an...

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Bibliographic Details
Published in:Chemistry : a European journal 2023-04, Vol.29 (20), p.e202203914-n/a
Main Authors: Qiao, Xiu‐Xiu, He, Yonghui, Ma, Tao, Zou, Chang‐Peng, Wu, Xi‐Xi, Li, Ganpeng, Zhao, Xiao‐Jing
Format: Article
Language:English
Subjects:
2-aryl-3H-indol-3-ones
5-Aminopyrazoles
C2-quaternary indolin-3-ones
Chemistry
chiral phosphoric acids
dual H-bonds
Enantiomers
Friedel-Crafts reaction
Functional groups
Imines
Phosphoric acid
Pyrazole
Pyrazoles
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Summary:A chiral phosphoric acid‐catalyzed enantioselective aza‐Friedel–Crafts reaction of 5‐aminopyrazole derivatives with cyclic ketimines attached to a neutral functional group is reported. This protocol allows the formation of pyrazole‐based C2‐quaternary indolin‐3‐ones with high enantioselectivities and regioselectivities. Moreover, gram‐scale synthesis of the 5‐aminopyrazole‐based C2‐quaternary indolin‐3‐ones was performed, with no decrease in the yield and enantioselectivity. Herein, we describe a challenging chiral phosphoric acid‐catalyzed asymmetric aza‐Friedel–Crafts reaction of 5‐aminopyrazoles with cyclic‐ketimines attached to neutral functional group, achieving enantiomerically enriched pyrazole‐based C2‐quaternary indolin‐3‐ones with highly enantioselectivities and regioselectivities.
ISSN:0947-6539
1521-3765
DOI:10.1002/chem.202203914