Iron‐Catalyzed C−C and C−N Bond‐Forming Tandem Amidation Offering Access to 3‐Amino‐3‐Aminomethyl‐2‐Oxindole Frameworks

An iron‐catalyzed protocol for the synthesis of 3‐amino‐3‐aminomethyl‐2‐oxindole heterocyclic structures is disclosed employing isatins and non‐nucleophilic N‐methoxybenzamides. This reaction class is associated with broad scope and tolerates numerous functionalities, such as fluoro, chloro, bromo,...

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Bibliographic Details
Published in:Advanced synthesis & catalysis 2024-06, Vol.366 (12), p.2801-2810
Main Authors: Ankade, Shidheshwar B., Pradhan, Chandini, Paramita Samal, Pragnya, Gonnade, Rajesh G, Krishnamurty, Sailaja, Punji, Benudhar
Format: Article
Language:English
Subjects:
Benzamide
Benzothiophene
Chemical synthesis
Imines
Iron
isatin
tandem amidation
tetrasubstituted carbon stereocenter
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Summary:An iron‐catalyzed protocol for the synthesis of 3‐amino‐3‐aminomethyl‐2‐oxindole heterocyclic structures is disclosed employing isatins and non‐nucleophilic N‐methoxybenzamides. This reaction class is associated with broad scope and tolerates numerous functionalities, such as fluoro, chloro, bromo, iodo, trifluoromethyl, nitrile, ester, ether, and alkenyl, including heteroaryl – thiophene, benzothiophene, carbazolyl, indolyl, eugenol, and polycyclic cholesterol moieties. Detailed mechanistic investigations reveal that the reaction proceeds via iron‐catalyzed N−O bond cleavage in N‐methoxybenzamides, generating formaldehyde and benzamide, and through the intermediacy of isatin‐ketimines and N‐(hydroxymethyl)benzamides. Overall, this amidation reaction involves one C−C and two C−N bond‐forming tandem processes, providing a range of β‐amino‐aminomethyl‐oxindoles (45 examples) in up to 88% yields.
ISSN:1615-4150
1615-4169
DOI:10.1002/adsc.202400216