Metal-free three-component cyanoalkylation of quinoxalin-2(1H)-ones with vinylarenes and azobis(alkylcarbonitrile)s

Abstract

We have unveiled an efficient synthesis of cyanoalkylated quinoxalin-2(1H)-ones via a three-component radical cascade reaction of quinoxalin-2(1H)-ones with vinylarenes and azobis(alkylcarbonitrile)s. K2S2O8 takes part in the reaction as a sole...

Recent Advances on Radical-Mediated Cyanoalkylation/Cyanation using AIBN and Analogues as the Radical Sources

“…In 2022, Bhuyan and co-workers reported a multiple component radical cascade reaction initiated by AIBN. 25 In this example, no transition-metal catalyst was used, and K 2 S 2 O 8 was applied as oxidant. This approach represents a green cyanation methodology with no highly toxic nitrile source used.…”

K2S2O8 Mediated Three‐component Radical Cascade C3 Alkylation of Quinoxalin‐2(1H)‐ones with Vinylarenes and 4‐Hydroxycoumarins/4‐Hydroxy‐6‐methyl‐2‐pyrone

“…[64] Recently, radical difunctionalization of styrenes has been a topic of keen interest in organic synthesis as it leads to the formation of complex organic molecules in a single step with broad functional group tolerance. [65] Very recently, several research groups around the world have reported the threecomponent cascade C3 alkylation of quinoxalin-2(1H)-ones using olefins and styrenes as intermediary radical acceptors and different radical precursors such as perfluoroalkyl iodides, [66] TMSN 3 , [67] CF 3 SO 2 Na, [68] sulfinic acid, [69] DMSO, [70] and AIBN [71] to produce diverse 3-alkylated quinoxalin-2(1H)-one derivatives.…”

“…In 2020, we reported the cross-dehydrogenative coupling reaction of 4-hydroxycoumarins and 4-hydroxy-6-methyl-2pyrone with quinoxalin-2(1H)-ones. [72] Again, we have just published a three-component radical cascade reaction of quinoxalin-2(1H)-ones with vinylarenes and azobis(alkylcarbonitrile)s. [71] Based on the above two reports, we hypothesized the three-component radical cascade reaction of 4-hydroxycoumarins and 4-hydroxy-6-methyl-2-pyrone with quinoxalin-2(1H)-ones by using vinylarenes as intermediary radical acceptor might be feasible. In continuation of our research program (Scheme 1, [15,71,72] we, herein, wish to report a three-component reaction of quinoxalin-2(1H)-ones with 4hydroxycoumarins/4-hydroxy-6-methyl-2-pyrone and vinylarenes for the synthesis of 3-alkylated quinoxalin-2(1H)-ones using K 2 S 2 O 8 as the sole oxidant.…”

“…In 2020, we reported the cross‐dehydrogenative coupling reaction of 4‐hydroxycoumarins and 4‐hydroxy‐6‐methyl‐2‐pyrone with quinoxalin‐2(1 H )‐ones [72] . Again, we have just published a three‐component radical cascade reaction of quinoxalin‐2(1 H )‐ones with vinylarenes and azobis(alkylcarbonitrile)s [71] . Based on the above two reports, we hypothesized the three‐component radical cascade reaction of 4‐hydroxycoumarins and 4‐hydroxy‐6‐methyl‐2‐pyrone with quinoxalin‐2(1 H )‐ones by using vinylarenes as intermediary radical acceptor might be feasible.…”

“…Based on the above two reports, we hypothesized the three‐component radical cascade reaction of 4‐hydroxycoumarins and 4‐hydroxy‐6‐methyl‐2‐pyrone with quinoxalin‐2(1 H )‐ones by using vinylarenes as intermediary radical acceptor might be feasible. In continuation of our research program (Scheme 1, [15,71,72] we, herein, wish to report a three‐component reaction of quinoxalin‐2(1 H )‐ones with 4‐hydroxycoumarins/4‐hydroxy‐6‐methyl‐2‐pyrone and vinylarenes for the synthesis of 3‐alkylated quinoxalin‐2(1 H )‐ones using K 2 S 2 O 8 as the sole oxidant.…”