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Working Group Meeting March 2018 March 22 nd SALON DE ACTOS March 23 rd SALA DE CONFERENCIAS INTERNACIONALES Colegio Mayor de San Ildefonso Plaza San Diego s/n

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Working Group Meeting

March 2018

March 22nd

SALON DE ACTOS

March 23rd

SALA DE CONFERENCIAS INTERNACIONALES

Colegio Mayor de San Ildefonso 

Plaza San Diego s/n

Synthesis and reactivity of ethylene complexes of group 6 and 8 metals

María Álvarez,a Martin Albrechtb and Pedro J. Péreza

aLaboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química y Ciencia de Materiales, Universidad de Huelva, 21007 Huelva, Spain and

b Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland

[email protected]

Ethylene complexes constitute one of the classical families of organometallic compounds, and most of the transition metals are known to coordinate such ligand. In the context of the ethylene-carbon dioxide coupling reaction en route to acrylic acid derivatives,1 very few complexes have been described to promote such transformation. Only nickel, molybdenum and tungsten compounds bearing one (Ni) or two (Mo, W) ethylene ligands have been described promoting a given reaction toward carbon dioxide.

We have revisited this chemistry with the aim of understanding the C2H4- CO2 interaction. With this idea in mind, we have prepared novel tris-ethylene complexes of Mo(0) and W(0) bearing a pincer P-N-P ligand, and investigated their interaction with carbon dioxide. Preliminary studies have shown that a mono-carbon dioxide, bis(ethylene) Mo(0) complex is formed as the first step, not only in solution but also in the solid state.

In a collaborative effort between our two laboratories, we have also studied dicationic Ru(II) complexes bearing a N-N-N pincer ligand. Its reactivity toward ethylene has led to unstable bis(ethylene) complexes, also of interest toward carbon dioxide coupling.

Reference

1. Limbach, M. Adv. Organomet. Chem. 2015, 63, 175.

Assembly of Peptides upon Sustainable C–H Functionalization Marcos San Segundo, Itziar Guerrero and Arkaitz Correa*

Department of Organic Chemistry-I, University of the Basque Country (UPV-EHU), Joxe Mari Korta R&D Center, Av. Tolosa 72 -20018 Donostia-San Sebastián.

[email protected]

Owing to the emergence of peptidomimetics at the forefront of pharmaceutical research and the limited availability of amino acid genetically encoded, the development of new methodologies for the straightforward chemical modification of α-amino carbonyl compounds represents a challenging task of prime scientific interest.[1] Although most classical α-functionalization methods are hitherto limited to carbanion chemistry and solid phase techniques, the last years have witnessed the upsurge of catalytic C−H functionalization approaches[2] as atom-economic and environmentally friendly means for the direct modification of peptide derivatives. In this communication we will described our latest results on the assembly of α-functionalized glycine derivatives and short peptides. We have developed cobalt-catalyzed selective alkylation and heteroarylation processes for the rapid synthesis of structurally diverse α-amino carbonyl compounds upon activation of the α-C(sp3)−H bond neighboring to the amino group (Scheme 1, path a).[3] Likewise, following a related α-C(sp3)−H oxida�on process, an efficient ligand-free Fe-catalyzed oxidative Ugi-type reaction toward the synthesis of α-amino amides from N,N-dimethylanilines will be disclosed (Scheme 1, path b).[4]

Scheme 1. Metal-catalyzed synthesis of α-amino carbonyl compounds.

Acknowledgements. We are grateful to MINECO (CTQ2016-78395-P) and Gobierno Vasco (IT_1033-16) for financial support. A. C. thanks MINECO for a Ramón y Cajal research contract (RYC-2012-09873). References [1] (a) Hu, Q.-Y.; Bertib, F.; Adamo, R. Chem. Soc. Rev. 2016, 45, 1691. (b) Boutureira, O.; Bernardes, G. J. L. Chem. Rev. 2015, 115, 2174. [2] (a) Sengupta, S.; Mehta, G. Tetrahedron Lett. 2017, 58, 1357. (b) He, G.; Wang, B.; Nack, W. A.; Chen, G. Acc. Chem. Res. 2016, 49, 635. (c) Noisier, A. F. M.; Brimble, M. A. Chem. Rev. 2014, 114, 8775. For general reviews on cross-dehydrogenative couplings, see: (c) Yi, H.; Zhang, G.; Wang, H.; Huang, Z.; Wang, J.; Singh, A. K.; Lei, A. Chem. Rev. 2017, 117, 9016. (d) Lv, L.; Li, Z. Top. Curr. Chem. 2016, 374, 225. (e) Girard, S. A.; Knauber, T.; Li, C.-J. Angew. Chem., Int. Ed. 2014, 53, 74. [3] San Segundo, M.; Guerrero, I.; Correa, A. Org. Lett. 2017, 19, 5288. [4] Guerrero, I.; San Segundo, M.; Correa, A. Chem. Commun. 2018, early view

Direct Arylation of Dipyrrolonaphthyridinediones (DPNDs) Leads to Red-Emitting Dyes with Conformational Freedom

Daniel Gryko [email protected]

The series of bis-aryl-dipyrrolonaphthyridinediones (DPNDs) with different substitution patterns have been designed and synthesized via direct arylation methodology. This reaction occurs regioselectively at positions 3 and 9, thus giving a straightforward entry to unique dyes absorbing in the red/far-red region and emitting in the far-red/NIR region. The photophysical properties, such as absorption or fluorescence wavelengths can be controlled via altering the steric hindrance and electronic character of the peripheral aryl group. The fluorescence quantum yields are moderate in the majority of cases and almost independent of changes in the solvent polarity. DPNDs bearing sterically hindered substituents, which prevent free rotation of the phenyl ring, emit stronger fluorescence (~0.60 vs ~0.45). Simultaneously, their absorption and emission bands are blue-shifted compared to unhindered para analogs. We have explained, by means of computational methods, why the introduction of electrondonating substituents has significantly stronger effects on optical properties compared to the presence of electron-withdrawing groups by invoking the electron-accepting character of the dipyrrolonaphthyridinedione. Electrochemical measurements revealed that HOMO and LUMO levels, as well as the electrochemical band gap also depend strongly on the electronic character of the peripheral group.

Orthopalladated complexes from substituted oxazolones, imidazolones and thiazolones, and their photophysical properties

Alejandro Pueyo, Dario Cortés, Jaime Guerrero, Esteban P. Urriolabeitia (ISQCH-Zaragoza) Sandra Collado, Christine Baudequin, Laurent Bischoff, Christophe Hoarau (INSA-Rouen)

[email protected]

The synthesis of orthopalladated derivatives of oxazolones, imidazolones and thiazolones is reported. The reaction takes place through a directed C-H bond activation process, by treatment of the free ligands with Pd(OAc)2 in carboxylic acid as a solvent. The reaction is fully regioselective, because only the ortho-protons of the Ph ring at the 4-position (the arylidene ring) are activated, regardless the substituents at the arylidene ring and the electronic nature of the heterocycle (oxazolone, imidazolone, thiazolone). Standard bidentate and new tridentate systems containing the heterocyclic moiety have been attempted, with excellent results in all cases. In addition, the carboxylate bridges have been changed by a variety of anionic ligands, such as chloride, acetylacetonate, alkynyl, etc, giving a wide variety of dinuclear and mononuclear derivatives.

The photophysical properties of these systems have also been studied, in order to check the influence of the palladium, the nature of the heterocycle, the substituents in the orthopalladated heterocyclic ligand, and the auxiliary ligands in the fluorescence of the resulting complexes.

Gas-Liquid Catellani type Reactions enabled by continuous flow Alessandra Casnati, Hannes P. L. Gemoets, Elena Motti, Nicola Della Ca’, Timothy Noël

The selective activation and functionalization of inert C-H bonds is a great challenge in synthetic chemistryi. In 1997 Marta Catellani et al reported a pioneering strategy to functionalize both the ortho and ipso positions of aryl halidesii. Over the past two decades the Catellani reaction was intensely investigated, and a variety of compounds has been obtainediii. Owing to its wide applicability and versatility, the Catellani reaction might be intriguing towards industrial applications. In this regards, continuous flow is a valuable choice to easily and safely perform a reaction scale-upiv. During the last years flow technologies have received remarkable attentionv, their importance is attributed to the many benefits flow possesses with respect to conventional batch transformations. Among these, frequently described advantages are enhanced heat and mass transfer, large scale applications and better mixing. The latter is especially important in multiphase systems. Gaseous reagents are used in a large stoichiometric excess when batch conditions are employed, because of poor interfacial mixingvi. This can outcome in longer reaction time, making the process extremely slow. Continuous flow guarantees a high surface area to volume ratio, that allows an increase in mass transfer and thus accelerates reaction kinetics when mass transfer is rate limiting. Our first issue was to transform the reaction procedures into homogeneous conditions for flow. Our base, K2CO3 which is not completely soluble in the reaction media, was causing issues when translating the reaction to flow. Continuous flow technology, especially micro-flow setup, performs better if solid reagent are avoided. This prevents clogging and ensures an ideal mass transfer. After a carful survey of bases, tetrabutylammonium acetate (TBAA) proved its value by granting full conversion in 2 hours, while being completely miscible in DMF.

A new and efficient flow methodology was developed. To test the robustness of the novel approach, different molecules were synthetized employing liquid-liquid conditions. Moreover we devoted specific attention to employ gaseous reagents, which can highly benefit from continuous-flow conditions. Ethylene, propylene and 3,3,3-trifluoro-1-propene were engaged as starting materials, allowing the possibility to insert these moieties in the targeting molecules. i (a) J. Wencel-Delord, T. Dröge, F. Liu, F. Glorius, Chem. Soc. Rev. 2011, 40, 4740–4761. (b) O. Daugulis, H-Q. Do, D. Shabashov, Acc. Chem. Res. 2009, 42, 1074–1086. (c) S. R. Neufeldt, M. S. Sanford, Acc. Chem. Res. 2012, 45, 936−946. (d) G. Rouquet, N. Chatani, Angew. Chem., Int. Ed. 2013, 52, 11726−11743. (e) D-S. Kim, W-I. Park, and C-H. Jun Chem. Rev. 2017, 117, 8977−9015 ii M. Catellani, F. Frignani, A. Rangoni, A. Angew. Chem. Int. Ed. Engl. 1997, 36, 119–122 iii (a) J. Ye, M. Lautens, Nat. Chem. 2015, 7, 863-870. (b) N. Della Ca’, M. Fontana, E. Motti, M. Catellani, Acc. Chem. Res. 2016, 49, 1389-1400. iv (a) N. Kockmann, P. Thenée, C. Fleischer-Trebes, G. Laudadio, T. Noël, React. Chem. Eng. 2017, 2, 258–280. (b) Organometallic Flow Chemistry; Noël, T., Ed.; Springer, 2016. v (a) G. Jas, A. Kirschning, Chem. – Eur. J. 2003, 9, 5708-5723. (b) D. Webb, T. F. Jamison, Chem. Sci. 2010, 1, 675-680. (c) T. Noël, S. Buchwald, Chem. Soc. Rev. 2011, 40, 5010−5029. (d) V. Hessel, D. Kralisch, N. Kockmann, T. Noël, Q. Wang, ChemSusChem 2013, 6, 746−789. (e) R. Munirathinam, J. Huskens, W. Verboom, Adv. Synth. Catal. 2015, 357, 1093−1123. (f) B. Gutmann, D. Can�llo, C. O. Kappe, Angew. Chem., Int. Ed. 2015, 54, 6688−6728. (g) A. Gioiello, V. Mancino, P. Filipponi, S. Mostarda, B. Cerra, J. Flow Chem. 2016, 6, 167−180. (h) H. P. L. Gemoets, Y. Su, M. Shang, V. Hessel, R. Luque, T. Noël, Chem. Soc. Rev. 2016, 45, 83−117. (i) J. Bri� on, C. Raston, Chem. Soc. Rev. 2017, 46, 1250−1271. vi (a) M. B. Plutschack, B. Pieber, K. Gilmore, P. H. Seeberger, Chem. Rev. 2017, DOI: 10.1021/acs.chemrev.7b00183. (b) C. J. Mallia, I. R. Baxendale Org. Process Res. Dev. 2016, 20, 327−360.

Halide-Catalysed C-H Amination Reactions

Kilian Muñiz

Institute of Chemical Research of Catalonia (ICIQ)

The development of light-initiated catalytic C-H amination processes (Hofmann-Löffler reactions) has been accomplished using novel halogen-based catalysts that are directly generated from molecular iodine1,2 or from ammonium bromide3 sources. These processes can be tuned to involve either halogen(-I/I) or halogen(I/III) catalyst states. The specific iodine redox cycle depends on the chosen terminal oxidant, which can be an iodine(III) reagent or molecular dioxygen within photocatalysis, and which is commercially available mCPBA for the bromine redox cycle. The reactions proceed within a unique scenario of two intertwined catalytic cycles with an unprecedented scope including primary, secondary and tertiary C-H bonds. Mechanistic details include the isolation and study of active catalyst derivatives. These accomplishments demonstrate the rich facilities for C-H oxidation catalysis within defined halide redox manifolds.

[1] C. Martínez, K. Muñiz, Angew. Chem. Int. Ed. 2015, 54, 8287.

[2] P. Becker, T. Duhamel, J. C. Stein, M. Reiher, K. Muñiz, Angew. Chem. Int. Ed. 2017, 56, 8004.

[3] P. Becker, T. Duhamel, C. Martínez, K. Muñiz, manuscript under revision.

NR´

unfunctionalizedremote C-H bond

C-H amination products

NHSO2RR´

H

[visible light]R´´

R´´

or [blue LED]

TPT (1 mol%), air

I

iodine catalyst

Iodine catalysis with an iodine(III) Iodine catalysis with a photoredox-

ArCO2-I

Common N-iodinated intermediate

NR´

H

R´´

iodine catalystI-OH

I

elusive catalyst state(information by

computational chemistry)

oxidant(ArCO2)2IPh

oxidant

SO2R

SO2R

based terminal aerobic oxidationreagent as terminal oxidant

NSO2R

HNHSO2RH

H

Ar

ArBr

[visible light]unfunctionalizedremote C-H bond

C-H amination products

NPh Br

Tsiodine catalyst

Bromine catalysis with mCPBA

ArCO2-Broxidant

ArCO3H

as terminal oxidantIsolated N-brominated intermediate

Graphene Film-Supported Oriented 1.1.1 Gold (0) Versus 2.0.0 Copper (I) Nanoplatelets as Very Efficient Catalysts for Michael Additions

N. Candu1, A. Primo2, S.M. Coman1, H. Garcia2, V.I. Parvulescu1

1 University of Bucharest, B-dul Republicii 4-12, Bucharest 030016, Romania 2 Universitat Politécnica de Valencia, Av. De los Naranjos, 46022 Valencia, Spain

Metal nanoparticles (MNPs) supported on large surface area solids are widely used as heterogeneous catalysts for a large variety of organic reactions [1]. Theoretical calculations and experimental data suggest that different crystallographic planes of MNPs may exhibit specific activity in catalysis [2]. Therefore, one of the key issues for achieving high selectivities is the control of their preferential facets. In this context, the existing literature already suggests that carbon-nanotubes [3] and, more recently, graphene [4] provide interfaces with MNPs exhibiting specific electronic properties generated by the occurrence of a charge transfer between the carbon nanoform and the MNPs. In this context, we have recently reported a novel one-step pyrolysis procedure for the production of MNPs strongly grafted on few- and multilayer defective graphenes [5].

The catalysts in this study were prepared by pyrolysis of chitosan films containing AuCl4- or

Cu2+ ions rendering facet oriented Au and Cu nanoplatelets strongly grafted on defective N-doped graphene films. The number of layers depended on the thickness of the chitosan film precursor. C �u/͞fl-G undergoes upon exposure to the ambient preferentially oriented (2.0.0) copper(I) oxide nanoplatelets while Au3+ renders 1.1.1 oriented Au nanoplatelets (20 nm lateral size, 3–4 nm height) (A �u/͞fl-G). These nanometric films containing oriented nanoplatelets were investigated in the Michael addition reaction, which is one of the oldest and useful C-C bond-forming reactions [6]. This 1,4-addition is typically carried out using basic catalysts. The prepared catalysts were exhaustively characterized using different techniques as powder X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) [5, 7]. Activity tests were carried out by using aqueous solutions of β-ketoesters as Michael donor (methyl acetoacetate, ethyl acetoacetate; isobutyl acetoacetate, ethyl 2-oxocyclohexanecarboxylate or ethyl 2-oxocyclopentanecarboxylate) and methyl vinyl ketone, as Michael acceptor, at room temperature for 18h and one piece of 1 × 1 cm2 plate of A�u͞/fl-G or C �u/͞fl-G film as catalysts. The recovered products from the liquid phase were extracted with ethyl ethanoate and analyzed by GC-MS.

It has thus been shown that films of oriented 2.0.0 Cu2O and 1.1.1 Au nanoplatelets grafted onto few-layers graphene exhibit indeed activity in the Michael addition, with TONs higher than those of analogous Cu and Au catalysts adsorbed on graphene. These Cu2O and Au grafted on graphene also exhibit a remarkable catalytic activity to promote with total selectivity (in the absence of any extrinsic base) the Michael addition of acyclic and cyclic active methylene and methine compounds to α, β-conjugated ketone.

References 1. Tao F (2016) Metal Nanoparticles for Catalysis: Advances and Applications, RSC Catalysis Series,

RSC

2. Li, Z. Ciobanu C.V, Hu J., Palomares-Baez J.P, Rodriguez-Lopez J.L, Richards R., (2011) Phys.

Chem. Chem. Phys. 13, 2582–2589 3. Wildgoose G G, Banks CE, Compton RG (2006) Small 2,182–193 4. Ding M, Tang Y, Star A (2013) J Phys Chem Lett 4, 147–160. 5. Primo A, Alvaro M, Candu N, Coman S, Parvulescu VI, Garcia H (2015) Nat Commun 6, 8561. 6. Perlmutter P (1992) Conjugate Addition Reactions in Organic Synthesis. Pergamon Press,

Elmsford, NY 7. Primo A, Candu N, Coman S, Parvulescu V, Garcia H (2016) Angew Chem-Int Ed 55, 607-612.

Multicopper Cores and MOFs: New Catalysts for Mild Functionalization of

Alkane Feedstocks

Alexander M. Kirillov

University of Lisbon, Instituto Superior Técnico, Centro de Química Estrutural, Portugal [email protected]

This contribution will summarize our recent results on the design, self-assembly synthesis and catalytic application of various multicopper(II) coordination compounds (discrete complexes and metal-organic frameworks) derived from aminoalcohol and carboxylic acid building blocks.[1] The obtained copper(II) products were applied as highly efficient bioinspired (pre)catalysts for: (1) the mild oxidation of different alkanes by hydrogen peroxide into alcohols and ketones (“C–H to C–O functionalization”), and (2) the hydrocarboxylation of gaseous and liquid Cn alkanes, by carbon monoxide, water and potassium peroxodisulfate, into the corresponding Cn+1 carboxylic acids (“C–H to C–C functionalization”). Catalytic efficiency, substrate scope, mechanistic and selectivity features, role of promoters and effects of different reaction parameters will be discussed, with a particular emphasis on unusual promoting role of water in the Cu-catalyzed oxidative functionalization of alkanes. Other examples of functional metal-organic networks and related materials with prospective catalytic applications in C–H functionalization or degradation of organic water pollutants will be presented.[2] Collaborations within the COST CHAOS network will be highlighted.

Acknowledgements: This work was supported by the FCT (Portugal, UID/QUI/00100/2013) and the COST Action CA15106 (CHAOS).

References [1] (a) M.V. Kirillova, C.I.M. Santos, V. André, T.A. Fernandes, S.S.P. Dias, A.M. Kirillov, Inorg. Chem. Front. 2017, 4,

968; (b) M.V. Kirillova, C.I.M. Santos, W. Wu, Y. Tang, A.M. Kirillov, J. Mol. Catal. A. 2017, 426, 343. (c) T.A. Fernandes, C.I.M. Santos, V. André, S.S.P. Dias, M.V. Kirillova, A.M. Kirillov, Catal. Sci. Technol. 2016, 6, 4584; (d) T.A. Fernandes, C.I.M. Santos, V. André, J. Kłak, M.V. Kirillova, A.M. Kirillov, Inorg. Chem. 2016, 55, 125.

[2] (a) J. Gu, Y. Cai, X. Liang, J. Wu, Z. Shi, A.M. Kirillov, CrystEngComm, 2018, 20, 906. (b) K. Iqbal, A. Iqbal, A.M. Kirillov, C. Shan, W. Liu, Y. Tang, J. Mater. Chem. A, 2018, 6, 2018. (c) J. Gu, X. Liang, Y. Cai, J. Wu, Z. Shi, A.M. Kirillov, Dalton Trans. 2017, 46, 10908.

Artificial Photoenzymes for Solar Photocatalytic Hydrogen Atom Transfer Reactions

Günther Knör

[email protected]

The Mechanism of the Palladium-Catalyzed Aerobic Homocoupling of Alkynes: A more Complex Oxidase-type Reaction

Ana Albeniz

[email protected]

A combined experimental and computational approach has been used to shed some light on the mechanism of the Pd-catalyzed oxidative homocoupling of alkynes using oxygen as oxidant. Besides its synthetic interest, this reaction is a competitive process in coupling reactions involving terminal alkynes but no detailed study was available so far on how this reaction occurs.

C3 arylation of furfural derivatives via catalytic C-H bond activation

Filipa Siopa [email protected]

The development of biorenewable chemical building blocks for chemical based commodities is an important issue. Carbohydrates are valuable resources for the generation of synthetic building blocks. Among them, glucose and xylose can be used without competing with the food sector being known their transformation to the furan functionality such as 5-(hydroxymethyl)furfural(HMF), and furfural respectively.[1] Recently, this team explored the Ru-catalyzed hydrofurylation of alkenes, involving a directed C−H ac�va�on at C3 of the furan ring.[2]

Here in, is presented a new functionalization of the biomass derived compounds furfural and HMF at C-3 position (Scheme 1) via catalytic C-H activation directed by temporary pendant group attached to the furan ring as imine via Ru-catalyzed hydroarylation of olefins.

Scheme 1. Overview of the C-3 position activation of furfural and derivatives.

The optimization of reactions conditions were performed and the reaction scope evaluated.[3] This atom-economical strategy has potential for an array of direct applications in Ru(0)-catalyzed C−H bond aryla�ons using removable direc�ng groups

[1] Mariscal, R.; Maireles-Torres, P.; Ojeda, M.; Sádaba, I.; López Granados, M. Energy Environ. Sci. 2016, 9, 1144. Rosatella, A. A.; Simeonov, S. P.; Frade, R. F. M.; Afonso, C. A. M. Green Chem. 2011, 13, 754. [2] Pezzetta, C; Veiros, L; Oble, J.;Poli, G.; Chem. Eur J., 2017, 23, 8385. [3] Hu, F.; Szostak, M. Org. Lett. 2016, 18 (17), 4186.

Process Development@Merck

Philipp Hans Fackler.

Process development paves the way for research substances in becoming valuable and accessible products. The talk will give a short overview of chemical process development at Merck with a focus on the organizational set-up and main working areas.