Reactions catalyzed by a binuclear copper complex: selective oxidation of alkenes to carbonyls with O₂

Abstract

A binuclear copper complex bearing a simple salicylate ligand catalyses the efficient cleavage of styrenes into ketones and aldehydes with O2 as the oxidant. The reaction works under an atmosphere of O2 (balloon) with 0.5 mol% of catalyst and could be performed on a gram scale, providing an alternative to ozonolysis.

Highly Efficient Binuclear Copper‐catalyzed Oxidation of N,N‐Dimethylanilines with O2

“…[13b,27] Alternatively, the iminium cation of 13 might be attacked by H 2 O to undergo hydrolysis reaction to give the demethylated product 4 a and formaldehyde via 15 (Scheme 6). [28] In summary, this study shows that structurally well-defined binuclear copper-salicylate complex 1 reported by us before [18][19][20] is a powerful catalyst for the aerobic oxidation of N,N-dimethylanilines. The reactions were carried out under very low loading of the binuclear copper catalyst with an oxygen balloon being sufficient in most cases.…”

“…[17] Recently, we have discovered that a binuclear paddle-wheel copper salicylate complex, [Cu(Sal) 2 NCMe)] 2 (Sal = salicylate) 1, readily prepared from simple CuCl and salicylic acid as fine green crystals, can serve as effective catalyst for the aerobic cross dehydrogenative coupling of N-aryltetrahydroisoquinolines, [18] the aerobic oxidation of amines to amides with the aid of a vitamin B1 analogue, [19] as well as the selective oxidation of alkenes to carbonyls with O 2 . [20] Herein, we report that 1 could catalyze the aerobic oxidation of N,N-dimethylanilines to N-methyl-N-phenylformamides as the major products by O 2 with TBAC (tetrabutylammonium chloride) and NaBF 4 as additives, without the aid of a vitamin B1 analogue (Scheme 1c).…”

“…The reason for the acceleration effect of NaBF 4 is unclear at present; As ionic intermediates are produced during the reaction, a possible role of NaBF 4 in the reaction is to increase the ionic strength of the reaction media to stabilize the ionic species during the reaction. Investigation of the solvent effect revealed that MeCN is the best solvent for the reaction; Other solvents, such as MeOH, DMF, DMSO, toluene, 1,4dioxane and DCM are not good for the reaction (SI, Table S1, entries [18][19][20][21][22][23][24]. Although DCE was effective for the reaction, it was inferior to MeCN (SI, Table S1, entry 14).…”

Oxidative Cleavage of Alkenes by O2 with a Non-Heme Manganese Catalyst

“…In addition to the chemical methods, enzymatic methods have been explored; however, they are limited by substrate specificity (Scheme e). Following on from our recent study of aerobic cleavage of styrene derivatives with molecular iron and copper catalysts, , herein, we report that the merger of a non-heme Mn­(II) catalyst with visible light enables the oxidative cleavage of both aromatic and aliphatic alkenes under 1 atm of O 2 at room temperature (Scheme ).…”

Cu(II)-silsesquioxanes as efficient precatalysts for Chan-Evans-Lam coupling

“…Among catalyzed reactions we could cite, e.g. selective oxidation of alkenes to carbonyls [11,12], oxidation of aliphatic and aromatic hydrocarbons [13e20], water oxidation [21,22], CeN and CeC couplings [23e25]. No less important process, namely, the oxidative coupling of nucleophiles with arylboronic acids (Chan-Evans-Lam (CEL) coupling), is also catalyzed by copper compounds.…”