Het doel van het onderzoek dat in dit proefschrift wordt beschreven was het ontwikkelen van nieuwe milieuvriendelijke en economisch duurzame methoden voor de selectieve oxidatie van organische verbindingen, in het bijzonder cis-dihydroxylering en epoxidatie van alkenen, oxidatie van alcoholen en aldehyden en selectieve C-H activatie. De voornaamste uitdaging was om deze reacties uit te voeren met een eenvoudige katalysator gebaseerd op mangaan en met waterstofperoxide. Tijdens het onderzoeksproject werd al snel een belangrijke doorbraak gemaakt: de ontdekking van een compleet nieuwe katalysator concept dat meteen geschikt was voor toepassingen op zowel het lab als in de industrie en het werd vervolgens gepatenteerd in samenwerking met industriële partners in het project. De voornaamste focus van het promotieonderzoek was om te ontrafelen hoe dit katalysator systeem werkt en om te komen tot verbeterd inzicht zodat het katalysator systeem nog bredere toepassing kan vinden in de toekomst

Saisaha, Pattama

NARCIS 

Manganese catalysed oxidations with hydrogen peroxide: applications and mechanistic insights

University of Groningen

   University of GroningenManganese catalysed oxidations with hydrogen peroxideSaisaha, PattamaIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:2012Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Saisaha, P. (2012). Manganese catalysed oxidations with hydrogen peroxide: applications and mechanisticinsights. Groningen: s.n.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 12-11-2019     Summary      160  Summary The goal of the research described in this thesis was to develop new methods for oxidative transformations of organic substrates including cis-dihydroxylation and epoxidation of alkenes, oxidation of alcohols, aldehydes and C-H activation, that are suitable for both laboratory and industrial scale. The research is based on atom-efficient and environmentally friendly concepts where manganese, a 1st row transition metal, and H2O2, as terminal oxidant, are used. Moreover, the mechanistic insights gained from the systems developed were essential for understanding how the catalysts work, which has proven vital to improve the present systems and develop the new systems.       The first catalytic system described in this thesis employs the combination of [MnIV,IV2O3(TMTACN)2]2+ and carboxylic acids as the catalyst and H2O2 as terminal oxidant. This catalyst has a long history which began in the late 1980s as model systems for the water splitting component of photosystem II (PS II) and dinuclear manganese-based catalase enzymes.1 Later, several research groups focused on applying this catalyst in oxidative transformations with initial efforts focussing on the use of additives to suppress the H2O2 depleting catalase-type activity of the catalyst and enhance its activity towards the oxidation of alkenes.2,3,4,5,6,7 Our research group also demonstrated the use of carboxylic acids as an additive, which is responsible for suppressing the catalase-type activity as well as tuning the reactivity and selectivity of the reactions.6,7   Studies revealed that bis-carboxylato bridged complexes [MnIII,III2O(RCO2)2(TMTACN)2]2+ were the active intermediate formed in the system.7 In this thesis, these bis-carboxylato bridged complexes obtained from pre-treatment of [MnIV,IV2O3(TMTACN)2]2+ with a carboxylic acid and H2O2 were used as the catalyst for the oxidative transformation of organic substrates. In general, this system showed a broad substrate scope and moderate to excellent conversion and isolated yield for the transformation of secondary alcohols and aldehydes to their corresponding ketones and carboxylic acids, respectively, as well as the oxidation of alkenes to their corresponding epoxides or cis-diols. Oxidation of primary alcohols is more challenging. However, varying the carboxylic acid co-catalyst and adding the catalyst batchwise improved conversions. High selectivity for C-H activation to mono-ketone products was also observed.   This method can be viewed as a practical method for small to large scale synthesis since the TMTACN ligand and its manganese complexes are cost-effective catalysts and can be obtained from large scale synthesis. Also, the conditions employed required low catalyst loading (generally 0.1 mol%) and near-stoichiometric amounts of H2O2. Moreover, the activity and selectivity of the reaction, especially for substrates containing multifunctional groups, can be tuned by varying the carboxylic acid co-catalyst and the amount of H2O2 used.        161   Summary Polypyridyl amine based ligands such as TPTN or TPEN ligands are a quite attractive class of ligands because their synthetic route allows for the facile introduction of various groups either on the central diamine unit or by replacing one or more of the pyridyl rings. Also, they showed some activity in the epoxidation of alkenes as well as the oxidation of alcohols to their corresponding ketones or aldehydes.8,9 The intermediate compounds containing the aminal motif in the synthetic route to TPTN/TPEN type ligands were tested as a new ligand class in manganese catalysed reactions. The substrate conversion and product distribution from aminal based ligands were identical to that observed with TPEN based ligand.   Ligand stability is a general issue that needs attention since it can control the reactivity and especially (enantio)selectivity of a reaction. Hence systems containing TPTN and aminal based ligands were studied and both showed that the ligand used decomposed under the reaction conditions employed to form the same species, i.e. pyridine-2-carboxylic acid. Furthermore, it was demonstrated that, for example, replacement of the TPTN ligand by an equivalent amount of pyridine-2-carboxylic acid in the oxidation reactions results in identical activity and selectivity for a broad range of substrates. In general, it might be expected that ligand degradation would lead to loss of activity in a catalytic system. This particular case demonstrated clearly that this is not necessarily true.   Although ligand degradation to pyridine-2-carboxylic acid is responsible for the conversion observed under slightly basic conditions in the presence of ketones, this does not mean that polypyridyl amine ligands cannot be used with manganese in oxidation catalysis when H2O2 is used as terminal oxidant. It should be remembered that Costas and coworkers showed the use of this type of ligand for the epoxidation of alkenes under acidic conditions.10 This demonstrated that the reaction conditions are crucial for the stability of ligand as well as the performance of the catalyst.  The discovery of ligand decomposition leads to a new catalytic system for the oxidation of alkenes based on MnII salt, H2O2 and a base in ketone containing solvents. This is a relatively simple ligand/metal system and holds remarkable potential in achieving synthetically useful selective oxidative transformations.   The presence of a ketone either as a solvent or cosolvent was found to be essential to the activity of the catalytic system. However, the use of a combination of acetone and H2O2 presents a substantial risk of explosion and hence may prove unsuitable for routine use especially on medium and large scale. Subsequently, butanedione was identified as a ketone that provided a highly active catalytic system and could be used substoichiometrically.11 Importantly, the reaction times were reduced dramatically, which is a key advantage in achieving higher selectivity.           162  Summary As mentioned before, one of the goals of the research was to understand how the catalyst works and to elucidate the reaction mechanism. The direct identification of an ‘active species’ or even the catalyst in its resting state was essentially impossible for this system because it is highly active and required very low amounts of catalyst.   Kinetic analysis employing Raman spectroscopy was used to obtain mechanistically relevant information about the system. This spectroscopic technique is useful since substantial information can be obtained from one measurement, e.g. conversion of substrate, product(s) formation and the presence of H2O2 and its adduct. The proposed mechanism of this system is shown in Scheme 1 and it is based on the observation of the equilibrium between butanedione and H2O2 towards 3-hydroperoxy-3-hydroxybutan-2-one, data obtained from the order of the reaction experiments and 18O-labelling studies.       Scheme 1 Proposed mechanism for the oxidation of alkenes under the MnII/pyridine-2-carboxylic acid/butanedione and a base system based on data from kinetic analyses and orders of the reaction.  163   Summary In summary, the results and discussion presented in this thesis set a solid basis for the development of potentially important oxidation methods. Further work will focus on demonstrating their applicability as a general synthetic tool.   References                                                   1  K. Wieghardt, U. Bossek, B. Nuber, J. Weiss, J. Bonvoisin, M. Corbella, S. E. Vitols and J. J. Girerd, J. Am. Chem. Soc., 1988, 110, 7398. 2  D. E. De Vos and T. Bein, J. Organomet. Chem., 1996, 520, 195. 3  A. Berkessel and C. A. Sklorz, Tetrahedron Lett., 1999, 40, 7965.  4  J. Brinksma, L. Schmieder, G. van Vliet, R. Boaron, R. Hage, D. E. De Vos, P. L. Alsters and B. L. Feringa, Tetrahedron Lett., 2002, 43, 2619. 5  (a) G. B. Shul'pin, G. Suss-Fink and J. R. Lindsay Smith, Tetrahedron, 1999, 55, 5345; (b) G. B. Shul'pin, G. Suss-Fink and L. S. Shul'pina, J. Mol. Cat. A – Chem., 2001, 170, 17. 6  J. W. de Boer, J. Brinksma, W. R. Browne, A. Meetsma, P. L. Alsters, R. Hage and B. L. Feringa, J. Am. Chem. Soc., 2005, 127, 7990. 7  J. W. de Boer, W. R. Browne, J. Brinksma, A. Meetsma, P. L. Alsters, R. Hage and B. L. Feringa, Inorg. Chem., 2007, 46, 6353. 8  J. Brinksma, R. Hage, J. Kerschner and B. L. Feringa, Chem. Commun., 2000, 537. 9  J. Brinksma, M. T. Rispens, R. Hage and B. L. Feringa, Inorg. Chim. Acta, 2002, 337, 75. 10  I. Garcia-Bosch, X. Ribas and M. Costas, Adv. Synth. Catal., 2009, 351, 348.   11  J. Dong, P. Saisaha, T. G. Meinds, P. L. Alsters, E. G. Ijpeij, R. P. van Summeren, B. Mao, M. Fañanás-Mastral, J. W. de Boer, R. Hage, B. L. Feringa and W. R. Browne, ACS Catal., 2012, 2, 1087. 

Manganese catalysed oxidations with hydrogen peroxide:applications and mechanistic insights

ARTS repository - University of Groningen

English

University of Groningen Research Database

  
 University of Groningen
Manganese catalysed oxidations with hydrogen peroxide
Saisaha, Pattama
IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from
it. Please check the document version below.
Document Version
Publisher's PDF, also known as Version of record
Publication date:
2012
Link to publication in University of Groningen/UMCG research database
Citation for published version (APA):
Saisaha, P. (2012). Manganese catalysed oxidations with hydrogen peroxide: applications and mechanistic
insights Groningen: s.n.
Copyright
Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the
author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).
Take-down policy
If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately
and investigate your claim.
Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the
number of authors shown on this cover page is limited to 10 maximum.
Download date: 10-02-2018
 
  
Table of Contents 
 
Chapter 1 Mechanisms in manganese catalysed oxidation of alkenes  
with H2O2           1 
1.1 Introduction         2 
1.2 Studying mechanism in manganese catalysed oxidation chemistry:                                
 tools of the trade        2 
1.3 Oxidations catalysed by ‘ligand free’ Mn systems    3 
1.4 Quinoline based ligands for manganese catalysed oxidation   7 
1.5 Polypyridyl amine based ligands for manganese catalysed                                        
 oxidation          8 
1.6 Trimethyl-triazacyclononane based ligands for manganese                                    
 catalysed oxidation        12 
1.7 Tetraazamacrocycle based ligands for manganese catalysed                                     
 oxidation          21 
1.8 Conclusions         23 
1.9 Overview of the thesis        23 
1.10 References and notes        24 
 
Chapter 2 Selective catalytic oxidation of alcohols, aldehydes, alkanes                     
and alkenes employing manganese catalysts and H2O2    29 
2.1 Introduction         30 
2.2 Results and discussion        31 
 2.2.1 Oxidation of secondary alcohols to ketones    31 
 2.2.2 Oxidation of primary and benzyl alcohols to carboxylic acids  34 
 2.2.3 Oxidation of aldehydes to carboxylic acids    36 
 2.2.4 Oxidation of alkenes       38 
 2.2.5 C-H activation        41 
 2.2.6 Oxidation of bifunctional substrates     43 
 2.2.7 Protecting group tolerance      48 
2.3 Summary and conclusions       50 
2.4 Experimental section        51 
2.5 References and notes        66 
        
Chapter 3 The unexpected role of pyridine-2-carboxylic acid in                               
manganese based oxidation catalysis with pyridin-2-yl based ligands  69 
3.1 Introduction         70 
3.2 Results          73 
 3.2.1 Catalytic activity of MnII with TPTN, 2 and 3    73 
 3.2.2 Stability of ligands 2 and 3 in the presence of iron salts and                            
  under acid and basic conditions      74 
 3.2.3 Catalytic activity of MnII/ligand in relation to ligand structure  77 
 3.2.4 Ligand stability under reaction conditions    79 
 3.2.5 Oxidation catalysis with pyridine-2-carboxylic acid/MnII  80 
 3.2.6 C-H activation and alcohol oxidation with pyridine-2-                                
  carboxylic acid/MnII/NaOAc      82 
3.3 Summary and conclusions       82 
3.4 Experimental section        83 
3.5 References and notes        95 
 
Chapter 4 Manganese catalysed cis-dihydroxylation of electron deficient                                 
alkenes with H2O2         99 
4.1 Introduction         100 
4.2 Results and discussion        101 
 4.2.1 cis-Dihydroxylation of electron deficient alkenes   101 
 4.2.2 cis-Dihydroxylation and epoxidation of electron rich alkenes  106 
 4.2.3 Catalyst composition       107 
 4.2.4 Solvent dependence       110 
4.3 Mechanistic considerations       111 
4.4 Summary and conclusions       112 
4.5 Experimental section        113 
4.6 References and notes        120 
 
Chapter 5 Mechanistic study of an in situ prepared MnII/pyridine-2-                
carboxylic acid catalytic system       123 
5.1 Introduction         124 
5.2 Mechanistic considerations       125 
 5.2.1 Information from substrate scope     125 
 5.2.2 Kinetic analysis: order of reaction with respect to various                                
  components and the rate determining step    126 
 5.2.3 Role(s) of ketone in the catalytic reaction    131 
 5.2.4 Effect of acetic acid on the catalytic oxidation of alkenes  138 
 5.2.5 Effect of other acids on catalysis with butanedione   141 
 5.2.6 18O-labelling studies       147 
5.3 Proposed mechanism        149 
5.4 Summary and conclusions       151 
5.5 Experimental section        152 
5.6 References and notes        153 
 
Chapter 6 General discussion and future perspectives    155 
6.1 References          158 
 
Summary           159 
 
Samenvatting          165 
 
Acknowledgements         171 
 


Manganese catalysed oxidations with hydrogen peroxide:applications and mechanistic insights

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