Mechanistic Insight into the Light-Triggered CuAAC Reaction: Does Any of the Photocatalyst Go?

MARTÍNEZ-HAYA, REBECA; HEREDIA, ADRIÁN A.; CASTRO-GODOY, WILLBER D.; SCHMIDT, LUCIANA C.; MARIN, M. LUISA; ARGÜELLO, JUAN E.

JOURNAL OF ORGANIC CHEMISTRY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2021 vol. 86 p. 5832 - 5832

0022-3263

he attainment of transition-metal catalysis and photoredox catalysis has represented a great challenge over the last years. Herein, we have been able to merge both catalytic processes into what we have called ?the light-triggered CuAAC reaction?. Particularly, the CuAAC reaction reveals opposite outcomes depending on the nature of the photocatalyst (eosin Y disodium salt and riboflavin tetraacetate) and additives (DABCO, Et3N, and NaN3) employed. To get a better insight into the operating processes, steady-state, time-resolved emission, and laser flash photolysis experiments have been performed to determine reactivity and kinetic data. These results, in agreement with thermodynamic estimations based on reported data, support the proposed mechanisms. While for eosin Y (EY), Cu(II) was reduced by its triplet excited state; for riboflavin tetraacetate (RFTA), mainly triplet excited RFTA state photoreductions by electron donors as additives are mandatory, affording RFTA (from DABCO and Na