Photocatalyzed decarboxylation of oxamic acids under near-infrared conditions

Abstract

Photocatalyzed oxidative decarboxylation of oxamic acids under near-infrared irradiation using Os(bptpy)2(PF6)2 as catalyst is reported. The reaction was applied to the synthesis of urethanes and heterocyclic amides. Mechanistic studies and...

Applications of red light photoredox catalysis in organic synthesis

“…After the pioneering work of polypyridyl Os complexes for NIR photoredox catalysis was introduced by the Rovis group in 2020, 6 c several intriguing red light-induced Os complex-catalyzed reactions were also reported. 24–26…”

“…Very recently, Landais and co-workers also showed a red-light-mediated oxidative decarboxylation of oxamic acids 44 (Scheme 4c). 26 Using 4c as a PC and 1-acetoxy-1,2-benziodoxol-3(1 H )-one (BI-OAC) as an oxidant, 44 reacted with alcohols 45 or heteroarenes 47 , affording urethanes 46 or heterocyclic amides 48 successfully.…”

“…After the pioneering work of polypyridyl Os complexes for NIR photoredox catalysis was introduced by the Rovis group in 2020, 6c several intriguing red light-induced Os complex-catalyzed reactions were also reported. [24][25][26] In 2022, as a follow-up work, Rovis et al applied Os polypyridyl complex 4a in metallaphotoredox catalysis (Scheme 4a). 24 By combining NiBr 2 •H 2 O and PC 4a as the dual catalysts, a cross-coupling reaction between aryl bromides 39 and amines 40 was promoted under red light irradiation (660 nm).…”

Recent advances in catalytic decarboxylative transformations of carboxylic acid groups attached to a non-aromatic sp2or sp carbon

“…Likewise, an osmium( ii ) complex was found to promote the oxidative decarboxylation of oxamic acids under near-infrared irradiation during the synthesis of urethane 266b . 107 Alternatively, the isocyanates were formed from oxamic acids in the presence of the PANI(polyaniline)-g-C 3 N 4 -TiO 2 composite and a hypervalent iodine oxidant upon irradiation with visible light. 108 Isocyanate 269 was trapped in the form of unsymmetrical urea 267 in moderate to good yields (Scheme 94).…”

Iron-Catalyzed Oxidative Decarboxylation of Oxamic Acids: A Safe and Efficient Photochemical Route to Urethanes

“…Safety and environmental concerns thus prompted chemists to find alternative routes for the production of these useful intermediates, 7 using CO2 as a phosgene surrogate. 8 Amongst the many methods to access urethanes in this way, addition of amines to cyclic carbonates or to CO2 and alkylation of the resulting carbamic acid have thus attracted some attention. 8b,c Our laboratory has recently explored another route, 9 initiated in the 90's by Minisci and co-workers 10 using safe and readily available oxamic acids (1, Scheme 1).…”