Transition-Metal-Free Addition Reaction for the Synthesis of 3-(Aminobenzylidene/aminoalkylidene)indolin-2-ones and Its Synthetic Applications

Abstract

A novel and efficient transition-metal-free approach for the exclusive synthesis of Z-3-(aminobenzylidene/aminoalkylidene)­indolin-2-ones in high yield from 2-oxindole and aryl/alkyl nitrile in the presence of LiOtBu and 2,2′-bipyridine system is described. In addition, we disclosed a new approach towards the metal-free fluorination using selectfluor and the CC bond cleavage using CuI and environmentally benign O2.

Synthesis of Quaternary Spirooxindole 2H‐Azirines under Batch and Continuous Flow Condition and Metal Assisted Umpolung Reactivity for the Ring‐Opening Reaction

“…All the 3 (aminobenzylidene)oxindole derivatives were prepared according to literature procedure with approximately same yield [26] . Deuterated solvents were used as received.…”

Synthetic strategies for the construction of C3-fluorinated oxindoles

“…The reaction was further explored with different substituents at R 1 and R 2 affording the desired 66 in moderate yields (Scheme 25). 35…”

“…The reaction was further explored with different substituents at R 1 and R 2 affording the desired 66 in moderate yields (Scheme 25). 35 Hazra's group, in 2018, achieved asymmetric nucleophilic fluorination for the first time at the sp 3 -tertiary carbon to produce 3-fluoro-3-substituted oxindoles (68a-e) having excellent enantioselectivity. They used tetrabutylammonium fluor-…”

Synthesis of Fluorinated 3,6-Dihydropyridines and 2-(Fluoromethyl)pyridines by Electrophilic Fluorination of 1,2-Dihydropyridines with Selectfluor®

“…The electrophilic fluorination of aromatic heterocycles has been less studied than the fluorination of arenes. However, a number of fluoropyrroles [ 4 , 5 ], furans [ 6 ], thiophenes [ 7 ], pyrrolo[2,3-d]pyrimidines [ 8 , 9 ], quinolines [ 10 , 11 , 12 ] and indoles [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ] have been prepared either by direct fluorination or by fluorodecarboxylation using mainly Selectfluor ® and N -fluorobenzenesulfonimide.…”