Trichloromethyl‐Radical‐Initiated Three‐Component Reaction of Alkenes with CHCl₃ and Quinoxalinones

Abstract

An iron(II)-catalyzed three-component reaction was developed for the construction of trichloromethylated 3-benzylquinoxalin-2(1H)-ones. This reaction was conducted through the trichloromethylation of alkenes with quinoxalin-2(1H)-ones using commercially available chloroform as trichloromethyl radical source, which provided a convenient approach toward trichloromethylated 3-benzylquinoxalin-2(1H)-ones.

Metal-free polychloromethylation/cyclization of unactivated alkenes towards ring-fused tricyclic indolones and benzoimidazoles

“…Based on the experimental results and previous reports, 11,13 a possible mechanism is proposed in Scheme 4. Initially, under heating, the thermal homolytic cleavage of DTBP gives a tert -butoxy radical to initiate the radical cascade.…”

“…12 Our group has also made contributions to the radical polychloromethylation of alkenes toward complex di- and trichloromethylated structures especially heterocyclic structures. 13 For example, the polychloromethyl radical-initiated cyclization of unactivated N -alkene tethered alkenes formed polychloromethyl pyrrolo[1,2- a ]indoles and ring-fused quinazolinones (Scheme 1c and d). 4 g ,13 d As part of our ongoing interest in the radical polychloromethyl modification of valuable heterocyclic structures, herein, we describe our recent developments in the polychloromethylation-initiated cyclization of N -alkene tethered indoles toward ring-fused tri- and dichloromethylated indolones under metal-free conditions (Scheme 1e).…”

Iron‐Catalyzed Direct C3−H Trifluoromethylthiolation of Quinoxalin‐2(1H)‐ones

“…Subsequently, the Fe(II) is oxidized by K 2 S 2 O 8 to afford Fe(III) specie. Then, Fe(III) specie oxidize the radical intermediate C to form cation intermediate D [16b–c,25c] and regenerate Fe(II). Finally, the cation intermediate D is deprotonated to produce the desired product 3 a .…”

Three‐Component Reactions of Quinoxalin‐2(1H)‐ones: Recent Advances

“…This reaction has good substrate adaptation and functional group tolerance. Besides, Pan and coworkers [34] described a three‐component radical reaction of quinoxalin‐2(1 H )‐ones via iron(II)‐catalysis. The trichloromethylation of quinoxalin‐2(1 H )‐ones was achieved through a radical pathway to produce a variety of trichloromethylated 3‐benzylquinoxalin‐2(1 H )‐ones (35 examples, 15–84 % yields).…”