Modern Oxidation of Alcohols Using Environmentally Benign Oxidants

Arends, Isabel W. C. E.; Sheldon, R. A.

doi:10.1002/3527603689.ch4

Cited by 61 publications

(16 citation statements)

References 95 publications

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“…However, these traditional methods suffer from major shortcomings, which include the generation of a large amount of deleterious byproducts. Therefore, methods relying upon molecular oxygen or H 2 O 2 as a stoichiometric oxidant is more sustainable since it produces water as the sole byproduct. Among them, the issue of safety is a major concern for reactions with oxygen under elevated temperature .…”

Section: Resultsmentioning

confidence: 99%

Electronic Structure and Multicatalytic Features of Redox-Active Bis(arylimino)acenaphthene (BIAN)-Derived Ruthenium Complexes

et al. 2016

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The article examines the newly designed and structurally characterized redox-active BIAN-derived [Ru(trpy)(R-BIAN)Cl]ClO4 ([1a]ClO4-[1c]ClO4), [Ru(trpy)(R-BIAN)(H2O)](ClO4)2 ([3a](ClO4)2-[3c](ClO4)2), and BIAO-derived [Ru(trpy)(BIAO)Cl]ClO4 ([2a]ClO4) (trpy = 2,2':6',2''-terpyridine, R-BIAN = bis(arylimino)acenaphthene (R = H (1a(+), 3a(2+)), 4-OMe (1b(+), 3b(2+)), 4-NO2 (1c(+), 3c(2+)), BIAO = [N-(phenyl)imino]acenapthenone). The experimental (X-ray, (1)H NMR, spectroelectrochemistry, EPR) and DFT/TD-DFT calculations of 1a(n)-1c(n) or 2a(n) collectively establish {Ru(II)-BIAN(0)} or {Ru(II)-BIAO(0)} configuration in the native state, metal-based oxidation to {Ru(III)-BIAN(0)} or {Ru(III)-BIAO(0)}, and successive electron uptake processes by the α-diimine fragment, followed by trpy and naphthalene π-system of BIAN or BIAO, respectively. The impact of the electron-withdrawing NO2 function in the BIAN moiety in 1c(+) has been reflected in the five nearby reduction steps within the accessible potential limit of -2 V versus SCE, leading to a fully reduced BIAN(4-) state in [1c](4-). The aqua derivatives ({Ru(II)-OH2}, 3a(2+)-3c(2+)) undergo simultaneous 2e(-)/2H(+) transfer to the corresponding {Ru(IV)═O} state and the catalytic current associated with the Ru(IV)/Ru(V) response probably implies its involvement in the electrocatalytic water oxidation. The aqua derivatives (3a(2+)-3c(2+)) are efficient and selective precatalysts in transforming a wide variety of alkenes to corresponding epoxides in the presence of PhI(OAc)2 as an oxidant in CH2Cl2 at 298 K as well as oxidation of primary, secondary, and heterocyclic alcohols with a large substrate scope with H2O2 as the stoichiometric oxidant in CH3CN at 343 K. The involvement of the {Ru(IV)═O} intermediate as the active catalyst in both the oxidation processes has been ascertained via a sequence of experimental evidence.

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Section: Resultsmentioning

confidence: 99%

Electronic Structure and Multicatalytic Features of Redox-Active Bis(arylimino)acenaphthene (BIAN)-Derived Ruthenium Complexes

et al. 2016

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“…The oxidation of alcohols to carbonyl compounds is an important transformation in synthetic organic chemistry and extensive efforts have been focused on the development of atomeconomic oxidation methodologies for such reactions. [1][2][3][4] Amongst the protocols developed to date, catalytic aerobic oxidation has proven to be especially efficient and valuable by virtue of the use of a low-loaded, low-cost catalyst and molecular oxygen from the air. [5][6][7][8][9][10][11][12][13] In the past two decades, copper-catalysed, TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxyl) mediated aerobic oxidation has been the most popular choice of catalyst systems since the pioneering work of Semmelhack and coworkers in 1984.…”

Section: Introductionmentioning

confidence: 99%

Chiral tetranuclear and dinuclear copper(ii) complexes for TEMPO-mediated aerobic oxidation of alcohols: are four metal centres better than two?

et al. 2014

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ARTICLE This journal is © The Royal Society of Chemistry 2013J. Name., 2013, 00, 1-3 | 1 The one-pot reaction of 3,5-di-tert-butyl-2-hydroxybenzaldehyde, (R)-2-aminoglycinol and Cu(OAc)2·2H2O in a 1:1:1 ratio in the presence of triethylamine led to the isolation of X-ray quality crystals of the chiral complex (R)-1 in high yield. The single crystal structure of (R)-1 reveals a tetranuclear copper(II) complex that contains a {Cu4(μ-O)2(μ3-O)2N4O4} core. A reaction using (1S,2R)-2-amino-1,2-diphenylethanol as precursor under the same conditions generated the chiral complex (S,R)-2; its structure was determined by single crystal X-ray crystallography and was found to contain a {Cu2(μ-O)2N2O2} core. Both (R)-1 and (S,R)-2 have been used for catalytic aerobic oxidation of benzylic alcohols in combination with the TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxyl) radical. (R)-1 selectively catalyses the conversion of various aromatic primary alcohols to the corresponding aldehydes with high yields (99%) and TONs (up to 770) in the air, while (S,R)-2 exhibits less promising catalytic performance under the same reaction conditions. The role of the cluster structures in (R)-1 and (S,R)-2 in controlling the reactivity towards aerobic oxidation reactions is discussed. IntroductionThe oxidation of alcohols to carbonyl compounds is an important transformation in synthetic organic chemistry and extensive efforts have been focused on the development of atom-economic oxidation methodologies for such reactions. [1][2][3][4] Amongst the protocols developed to date, catalytic aerobic oxidation has proven to be especially efficient and valuable by virtue of the use of a low-loaded, low-cost catalyst and molecular oxygen from the air. [5][6][7][8][9][10] In the past two decades, copper-catalysed, TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxyl) mediated aerobic oxidation has been the most popular choice of catalyst systems since the pioneering work of Semmelhack and coworkers in 1984. These authors utilized a CuCl/TEMPO system in DMF (N,N-dimethylformamide) to furnish the aerobic oxidation of benzylic and allylic alcohols. 11 Recent progress indicates that both Cu(I) and Cu(II) complexes with a N,N-or N,O-ligands in combination with TEMPO could be efficient catalysts or catalyst precursors for the aerobic oxidation of various alcohols, and of particular note is a highly efficient copper/2,2'-bipyridine/TEMPO system developed by the Stahl group. 12-17 However, the types of organic ligands exploited in the copper catalyst systems are still limited and the structures of copper catalysts involved in the catalytic process are rarely explored. [17][18][19][20] The construction of metal-organic cluster compounds through self-assembly of predesigned ligands with appropriate metal ions is a prime research topic [21][22][23][24][25] Herein, we report the one-pot syntheses and crystal structures of two tetranuclear and dinuclear copper(II) complexes resulting from the in situ synthesis of chiral Schiff base ligands (Scheme 1), and their catalytic ap...

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“…However, most recommended processes are applicable only for the oxidation of activated substrates and as a consequence, large quantities of additives such as bases or electron transfer mediators are needed. 13,14 Nowadays, due to increasing environmental concerns, many efforts have been made to develop oxidation systems using environmentally benign molecular oxygen as a sole oxidant. In this respect, Ru-based oxidation catalysis becomes a powerful and extremely versatile synthetic tool to afford selective oxygenate products both under homogeneous and heterogeneous conversions with dioxygen, hydrogen peroxide or other easily accessible and environmentally friendly oxidants, or to the oxidative generation of O 2 from water.…”

Section: Introductionmentioning

confidence: 99%

Ru-based magnetic nanoparticles (MNP) for succinic acid synthesis from levulinic acid

et al. 2013

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Modern Oxidation of Alcohols Using Environmentally Benign Oxidants

Cited by 61 publications

References 95 publications

Electronic Structure and Multicatalytic Features of Redox-Active Bis(arylimino)acenaphthene (BIAN)-Derived Ruthenium Complexes

Electronic Structure and Multicatalytic Features of Redox-Active Bis(arylimino)acenaphthene (BIAN)-Derived Ruthenium Complexes

Chiral tetranuclear and dinuclear copper(ii) complexes for TEMPO-mediated aerobic oxidation of alcohols: are four metal centres better than two?

Ru-based magnetic nanoparticles (MNP) for succinic acid synthesis from levulinic acid

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