@article {48083,
	title = {Efficient route to 3,3 {\textquoteleft}-biindolinylidene-diones by iron-catalyzed dimerization of isatins},
	journal = {Chemistry-an Asian Journal},
	volume = {17},
	year = {2022},
	month = {AUG},
	pages = {e202200414},
	type = {Article},
	abstract = {<p>
	Iron-catalyzed dimerization of various isatin derivatives is described for the efficient synthesis of 3,3 {\textquoteleft}-biindolinylidene-diones (isoindigos). The reaction provides easy access to self-coupled and cross-coupled 3,3 {\textquoteleft}-indolinylidene-diones that have high relevance to biology and materials. This Fe(0)- or Fe(II)-catalyzed dimerization reaction tolerates a wide range of functionalities, such as fluoro, chloro, bromo, alkenyl, nitrile, ether, ester, pyrrolyl, indolyl and carbazolyl groups, including cyclic and acyclic alkyls as well as an alkyl-bearing fatty-alcohol moiety. Especially, the coupling between two distinct isatins provided excellent selectivity for the cross-dimerization with trace of self-couplings. The single-crystal X-ray diffraction study established the molecular structure of eight dimerized products. A preliminary mechanistic study of the Fe-catalyzed dimerization supported the radical pathway for the reaction.</p>
},
	keywords = {Cross-coupling, dimerization, iron, Isatin, Isoindigo, Mechanism},
	issn = {1861-4728},
	doi = {10.1002/asia.202200414},
	author = {Jagtap, Rahul A. and Pradhan, Chandini and Gonnade, Rajesh G. and Punji, Benudhar}
}
@article {49366,
	title = {Iron-catalyzed C-C and C-N bond-forming tandem amidation offering access to 3-amino-3-aminomethyl-2-oxindole frameworks},
	journal = {Advanced Synthesis \& Catalysis},
	volume = {366},
	year = {2024},
	month = {JUN },
	pages = {2801-2810},
	type = {Article},
	abstract = {<p>
	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 beta-amino-aminomethyl-oxindoles (45 examples) in up to 88\% yields. image</p>
},
	keywords = {benzamide, iron, Isatin, tandem amidation, tetrasubstituted carbon stereocenter},
	issn = {1615-4150},
	doi = {10.1002/adsc.202400216},
	author = {Ankade, Shidheshwar B. and Pradhan, Chandini and Samal, Pragnya Paramita and Gonnade, Rajesh G. and Krishnamurty, Sailaja and Punji, Benudhar}
}
