N‐Halosuccinimide‐CeCl3 Transient Charge‐Transfer Complexes as Semi Heterogeneous Photocatalyst in Cyclization of N‐Propargylamides

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(57)

Published: Aug. 1, 2024

In this work, we used photoinert anhydrous cerium(III) chloride, to form a transient charge-transfer (CT) complex with NXS (N-bromosuccinimide or NBS and N-iodosuccinimide NIS) in acetonitrile. These CT complexes acted as semi-heterogeneous photocatalyst. allowed the Ce(III) ions absorb light, turning them into strong electron donors that transferred electrons NXS. This created halide radicals from radical anions, helping turn N-propargylamides oxazole aldehydes. Experiments DMPO spin-trapping showed radical-based mechanism followed single transfer (SET) pathway. Notably, CeCl

Language: Английский

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Metal‐Free [2+3] Dipolar Cycloaddition/Denitration Cascade between Nitroalkenes and α‐Diazoesters: Regioselective Access to Functionalized NH−Pyrazoles

Asian Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 13(6)

Published: April 3, 2024

Abstract An efficient one‐pot synthesis of 1 H ‐pyrazoles has been realized via cascade cyclocondensation β‐nitroalkenes as C2 synthon with α‐diazoesters C1N2 unit. The reaction proceeds concomitant formation two new (C−N & C−C) bonds in one stretch leading to ethyl‐5‐nitro‐4‐phenyl‐4,5‐dihydro‐3 ‐pyrazole‐3‐carboxylate intermediate, which undergoes base mediated denitration enabling the NH−pyrazoles. This protocol not only features easy operation, catalyst−free conditions, good high yields, wide scope and late‐stage functionalization, but also opens up a avenue for synthetically demanding structurally non‐traditional pyrazoles. A combination experimental DFT studies provide evidence proposed mechanism.

Language: Английский

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Five-membered ring systems: With more than 1 N atom

Progress in heterocyclic chemistry, Journal Year: 2024, Volume and Issue: unknown, P. 211 - 257

Published: Jan. 1, 2024

Language: Английский

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