Weyl B,
Goujon G,
Raggio L,
Demey E,
Vinh J,
d’Espinose de Lacaillerie J-B,
Krafft J-M,
Laroche B *.
École Supérieure de Physique et de Chimie Industrielles de la ville de Paris (ESPCI), France
Visible Light Excitation of Poly(
para-phenylene ethynylene) Enables Heterogeneous Photocatalytic Oxidation of Amines in Flow.
Angew. Chem. Int. Ed. 2025;
64: e202419169
DOI:
10.1002/anie.202419169
Keywords
poly(phenylene ethynylene) - photocatalysis - aerobic oxidation - imines - Ugi reaction
Significance
Poly(phenylene ethynylene) (PAE) served as a heterogeneous photocatalyst to promote the oxidation of amines with molecular oxygen under photo-irradiation (white LED) conditions. Primary and secondary amines afforded the corresponding dimeric imines and dehydrogenative imines, respectively. The photocatalytic oxidation was carried out in batch as well as in flow, where the flow reaction proceeded in higher efficiency. Reusability of the PAE catalyst was confirmed both in batch and in flow.
Comment
The resulting stream of the flow photooxidation of benzylamine was mixed with a solution of cyclohexyl isocyanide and benzoic acid, and the mixture was directly engaged within a coil flow reactor (50 min residence time @ 50 °C) to give the Ugi condensation product 10 in 74 % yield via imine 1. No Ugi product was obtained by one-pot batch reaction of benzylamine, cyclohexyl isocyanide, and benzoic acid under the photooxidation conditions with the PAE catalyst.
