Iron-catalyzed cross-dehydrogenative coupling of indolin-2-ones with active methylenes for direct carbon–carbon double bond formation

Abstract

A novel iron-catalyzed cross-dehydrogenative coupling of two different C(sp3)–H bonds to synthesize olefins by using air as an ideal oxidant.

Crystal structure and Hirshfeld surface analysis of methyl 4′-amino-3′,5′-dicyano-2,2′′-dioxodispiro[indoline-3,1′-cyclopentane-2′,3′′-indolin]-3′-ene-5′-carboximidate with an unknown solvent

“…Cyclization of carbo-and heterocycles with the participation of malononitrile to obtain spiro compounds has been reported in the literature. (Zhu et al, 2016;Tan et al, 2020). In addition, it is known that the reaction of Hantzsch ester with two molecules of 2-(2-oxoindolin-3-ylidene)malononitrile, 1, leads to the formation of dispiro[cyclopent-3-ene]bisoxindoles, 2 .…”

Aerobic Cross-Dehydrogenative Coupling Reactions for Selective Mono- and Dithiolation of Phenols

“…Therefore, performing such transformations under transition-metal-free and solvent-free conditions and employing air as the oxidant is a dream reaction. Here, within our program on sustainable oxidation for C–C and C–heteroatom bond formation, we disclose an unprecedented base-air oxidation system for direct selective thiolation of arenes. This work has made notable achievements that include (1) a free hydroxyl group as a DG to control regioselectivity, (2) controlled temperature for selective mono- and dithiolation, (3) air (molecular oxygen) as the terminal oxidant, (4) performing under transition-metal-free and solvent-free conditions, and (5) readily available for large-scale synthesis.…”

Fe‐Catalyzed Intramolecular Cross‐Dehydrogenative Arylation (CDA), Efficient Synthesis of 1‐Arylnaphthalenes and 4‐Arylcoumarins

“…[53 -60] Many excellent works of iron-catalyzed CDC reactions involve C(sp 3 )H bond activation have been reported. [36,[61][62][63][64][65][66][67][68][69][70][71] In 2009, we developed a Fe-catalyzed cross-dehydrogenation coupling reaction of electron-rich aromatic hydrocarbons and diphenylmethane [36] (Scheme 1,b). Based on our continuous research on the field of transition-metalcatalyzed oxidative coupling of unactivated CÀ H bonds, [36,72,73] we here developed an inexpensive, readily available FeCl 3 /DDQ system to efficiently catalyze the tandem cross-dehydrogenative arylation/ oxidation reaction of 1,4-diphenylbutane and (3phenoxypropyl) benzene towards the synthesis of 1arylnaphthalenes and 4-arylcoumarins (Scheme 1,c).…”

“…Among all of the reported transition metals, Fe was brought into focus because of its low toxicity, popular price, and environmentally benign features [53–60] . Many excellent works of iron‐catalyzed CDC reactions involve C( sp 3 )H bond activation have been reported [36,61–71] . In 2009, we developed a Fe‐catalyzed cross‐dehydrogenation coupling reaction of electron‐rich aromatic hydrocarbons and diphenylmethane [36] ( Scheme 1 ,b ).…”