A new catalytic approach for aerobic oxidation of primary alcohols based on a Copper(I)-thiophene carbaldimines

• Novel in situ copper(I) iodide schiff base catalysts. High activity for the aerobic oxidation of benzylic, allylic and aliphatic alcohols. Quantitative yields benzaldehyde 3 h with a catalyst loading 2.5 mol%. Diol to corresponding lactol. We report here novel Cu(I) thiophene carbaldimine catalysts selective primary alcohols their aldehydes various diols lactones or lactols. In presence generated species, persistent radical (2,2,6,6-tetramethylpiperdine-N-oxyl (TEMPO)) N-methylimidazole (NMI) as an auxiliary ligand, reaction proceeds under conditions at ambient temperature. Especially catalytic system 1-(thiophen-2-yl)-N-(4-(trifluoromethoxy)phenyl)methanimine (ligand L2 ) copper(I)-iodide showed high reactivity all kind (benzylic, aliphatic). case benzyl alcohol even mol% copper gave quantitative yield. Beside conditions, ability oxidize 1,5-pentadiol lactol (86% 4 h) N-phenyldiethanolamine morpholine derivate 24 is particularly noteworthy.