The efficient synthesis of a sequence-defined decamer, its characterization, and its straightforward dimerization through self-metathesis are described. For this purpose, a monoprotected AB monomer was designed and used to synthesize a decamer bearing ten different and selectable side chains by iterative Passerini three-component reaction (P-3CR) and subsequent deprotection. The highly efficient procedure provided excellent yields and allows for the multigram-scale synthesis of such perfectly defined macromolecules. An olefin was introduced at the end of the synthesis, allowing the self-metathesis reaction of the resulting decamer to provide a sequence-defined 20-mer with a molecular weight of 7046.40 g mol⁻¹. The obtained oligomers were carefully characterized by NMR and IR spectroscopy, GPC and GPC coupled to ESI-MS, and mass spectrometry (FAB and orbitrap ESI-MS).

Hier wird ein effizienter Ansatz zur Synthese eines sequenzdefinierten Decamers, dessen Selbstmetathese sowie die Charakterisierung der erhaltenen Makromoleküle beschrieben. Zu diesem Zweck wurde ein monogeschütztes AB-Monomer synthetisiert und in einer Decamersynthese angewendet. Das erhaltene Decamer wurde durch iterative Verwendung der Passerini-Dreikomponenten-Reaktion (P-3CR) mit anschließender Entschützung hergestellt und trägt zehn unterschiedliche, wählbare Seitenketten. Dieser hocheffiziente Syntheseansatz ermöglichte exzellente Ausbeuten sowie die Synthese von perfekt sequenzdefinierten Makromolekülen im Multigramm-Maßstab. Am Ende der Synthese wurde ein Olefin als Seitenkette eingeführt, das eine Selbstmetathese-Reaktion des Decamers und damit die Synthese eines sequenzdefinierten 20-mers mit einem Molekulargewicht von 7046.40 g mol⁻¹ ermöglichte. Die erhaltenen Oligomere wurden vollständig mittels NMR- und IR-Spektroskopie, GPC, GPC-ESI-MS und Massenspektrometrie (FAB- und Orbitrap-ESI-MS) charakterisiert.

This work investigates acyclic diene metathesis (ADMET) polymerization reactions in aqueous miniemulsion. Different types of ruthenium-based catalysts and different surfactants (anionic, cationic, and nonionic) were evaluated. A Ru-indenylidene catalyst (Umicore M2) showed higher activity in water if compared to the Ru-benzylidene catalysts (Hoveyda Grubbs second generation and Grubbs first generation). Moreover, the catalyst activity was affected by the type of the surfactant. In summary, the Umicore M2 catalyst and the nonionic poly(ethylene oxide) based surfactant Lutensol AT80 were found to be the most suitable combination for ADMET reactions in miniemulsion allowing the preparation of polymers with number average molecular weight (M_n) of up to 15 kDa. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1300–1305

A new strategy to achieve sequence control in polymer chemistry based on the iterative application of the versatile Passerini three-component reaction (P-3CR) in combination with efficient thiol–ene addition reactions is introduced. First, stearic acid was used as a starting substrate to build up a sequence-defined tetramer with a molecular weight of 1.6 kDa. Using an acid-functionalized PEG allowed for an easier isolation of the sequence-defined macromolecules by simple precipitation and led to a sequence-defined pentamer in a block-copolymer architecture. Importantly, this new strategy completely avoids protecting group chemistry. By following this strategy, a different side chain can be introduced to the polymer/oligomer backbone in a simple way and at a defined position within the macromolecule.

In dieser Arbeit wird eine neue Strategie vorgestellt, die Sequenzkontrolle in der Polymerchemie ermöglicht. Der Ansatz basiert auf einer abwechselnden Verwendung der vielseitigen Passerini-Dreikomponentenreaktion (P-3CR) und der effizienten Thiol-En-Addition. Zunächst wurde Stearinsäure als Ausgangsmaterial gewählt, um ein Tetramer mit einem Molekulargewicht von 1.6 kDa und genau definierter Monomerabfolge zu synthetisieren. Die Aufreinigung nach den einzelnen Reaktionsschritten kann stark vereinfacht werden, indem ein funktionales Polymer mit einer Säure-Endgruppe als Ausgangssubstanz gewählt wird. Die Produkte konnten durch einfaches Ausfällen erhalten werden, sodass in einer effizienten Synthese ein sequenzkontrolliertes Pentamer hergestellt werden konnte. In diesem neuen Ansatz kann auf den Einsatz von Schutzgruppen verzichtet werden, und darüber hinaus können unterschiedliche Seitenketten mühelos und an definierten Stellen in das Polymerrückgrat eingebaut werden.

A new, highly efficient and environmentally benign catalytic variant of the Lossen rearrangement is described. Dimethyl carbonate (DMC) as green activation reagent of hydroxamic acids in presence of catalytic amounts of tertiary amine bases {1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,8-biazabicyclo 5.4.0 undec-7-ene (DBU), 1,4-diazabicyclo[2.2.2]octane (DABCO), and triethylamine} and small quantities of methanol initiate the rearrangement. Methyl carbamates were obtained in good to moderate yields when aliphatic hydroxamic acids were employed in this catalytic Lossen rearrangement; under the same conditions aromatic hydroxamic acids yielded anilines. Notably, the mixture of DMC/methanol was recycled several times without observing decreased yields, thus minimizing the produced waste. Moreover, several other organic carbonates were successfully employed in the introduced catalytic Lossen rearrangement procedure.

Two synthetic approaches to functionalize plant oil derived platform chemicals were investigated. For this purpose, methyl 10-undecenoate, which can be obtained by pyrolysis of castor oil, was used in olefin cross-metathesis under neat conditions forming an unsaturated α,ω-acetoxy ester. A catalyst screening with 11 different ruthenium-based metathesis catalysts was performed, revealing that well-suited catalysts allow for full conversion and very good cross-metathesis selectivity at a loading of only 0.5 mol%. An alternative possibility to the aforementioned synthetic method is a palladium-catalyzed reaction of methyl 10-undecenoate with acetic acid in the presence of dimethyl sulfoxide. Here, the formation of linear and branched unsaturated acetoxy esters as well as a ketone was observed. The conversion as well as the selectivity of this procedure was studied under different reaction conditions and compared to the cross-metathesis results. Based on the successful functionalization of methyl 10-undecenoate, methyl oleate was investigated in this palladium-catalyzed CH activation reaction. Due to the lower reactivity of the internal double bond the desired acetoxy ester was only obtained in moderate conversion in this case. In summary, this study clearly shows that palladium-catalyzed functionalization of unsaturated fatty compounds via CH activation is an attractive alternative to the well-established olefin cross-metathesis procedure.

This review covers the discovery and development of radical thiol-ene addition reactions as functionalization and polymerization method. First, some general and important developments within the field of polymer chemistry are introduced. However, the utilization of this efficient coupling procedure for the syntheses of materials derived from plant oils are the focus of this manuscript. Applications of this unique reaction will also be discussed in terms of green chemistry requirements as well as reaction conditions and efficiency.

Olefin cross-metathesis is introduced as a versatile polymer side-chain modification technique. The reaction of a poly(2-oxazoline) featuring terminal double bonds in the side chains with a variety of functional acrylates has been successfully performed in the presence of Hoveyda–Grubbs second-generation catalyst. Self-metathesis, which would lead to polymer–polymer coupling, can be avoided by using an excess of the cross-metathesis partner and a catalyst loading of 5 mol%. The results suggest that bulky acrylates reduce chain–chain coupling due to self-metathesis. Moreover, different functional groups such as alkyl chains, hydroxyl, and allyl acetate groups, as well as an oligomeric poly(ethylene glycol) and a perfluorinated alkyl chain have been grafted with quantitative conversions.

Oil from the Plukenetia conophora seed, a tropical oilseed consisting mainly of linolenic acid, is polymerized via acyclic triene metathesis using different ruthenium benzylidene and indenylidene catalysts to yield highly branched and functionalized polyesters. The influence of the synthesis conditions on the structure and molar mass characteristics of the obtained hyperbranched polyesters as well as an in-depth melt and solution material property investigation are presented.

One of the challenges of today's biodiesel (FAME) is its unsuitable boiling curve behavior. A more or less continuously increasing curve is beneficial because it provides good fuel ignition and combustion in the cylinder of the engine. Here, we present the results of our investigation on the chemical modification of biodiesel with the use of a well-known catalytic reaction, olefin metathesis. Self- and cross-metathesis of biodiesel and 1-hexene were carried out. Ten different ruthenium-based metathesis catalysts were initially subjected to a screening. After selection of the most active catalyst, a series of reactions were prepared wherein the concentration of the biodiesel was held constant, while the amount of 1-hexene was varied. The samples were then analyzed by simulated distillation to determine their boiling curve range. Results revealed that as the hexene amount was increased, a more favorable distillation curve was observed since it generated a fairly good distribution of low to high molecular weight compounds, which in turn exhibited an almost steadily increasing distillation curve, more similar to that of a conventional diesel fuel.

The self-metathesis of erucic acid with ruthenium-based catalysts, followed by the hydrogenation of the double bond, yielded 1,26-hexacosanedioic acid (AA). Polycondensation of this biobased long-chain α,ω-dicarboxylic acid with hexacosane-1,26-diol (BB), generated from the former by reduction, yielded the polyester 26,26. Monomer AA was also polymerized with short-chain alkanediols, namely dodecane-1,12-diol and butane-1,4-diol, generating polyesters 12,26 and 4,26, respectively. The properties of these aliphatic polyesters were investigated by various techniques, revealing high crystallinity, melting, and degradation temperatures, depending on the monomers used. These materials are an attractive alternative to fossil resource-based polymeric materials.

The ability of thiyl radicals to add to terminal unsaturations in an efficient way made them considered being one of the click reactions. Recently, thiol-yne addition reactions have been used extensively for the synthesis of crosslinked networks and dendrimers and postpolymerization functionalization protocols. Herein, we report a novel step-growth type reaction for highly functional linear polymers using a monoalkyne and dithiol compound. First, we investigated the model reaction between 1-octyne and 1-octanethiol as well as 1,4-butanedithiol compounds, which were initiated via self-, thermal-, and UV-initiation; the UV-initiation was found to be the most efficient method and completed within 2-h reaction time. The same conditions were applied for the polymerization of four different functional alkynes bearing different functional groups with two dithiol compounds. All polymerizations resulted in highly functional linear polymers with number averaged molecular weights ranging from 5 to 30 kDa, except for propargylic acid and its methyl ester, where only oligomers formed. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

The combination of the Ugi four-component reaction (Ugi-4CR) with acyclic diene metathesis (ADMET) or thiol–ene polymerization led to the formation of poly-1-(alkylcarbamoyl) carboxamides, a new class of substituted polyamides with amide moieties in the polymer backbone, as well as its side chains. 10-Undecenoic acid, obtained by pyrolysis of ricinoleic acid, the main fatty acid of castor oil, was used as the key renewable building block. The use of different primary amines, as well as isonitriles (isocyanides) for the described Ugi reactions provided monomers with high structural diversity. Furthermore, the possibility of versatile post-modification of functional groups in the side chains of the corresponding polymers should be of considerable interest in materials science. The obtained monomers were polymerized by ADMET, as well as thiol–ene, chemistry and all polymers were fully characterized. Finally, ortho-nitrobenzylamide-containing polyamides obtained by this route were shown to be photoresponsive and exhibited a dramatic change of their properties upon irradiation with light.

Pflanzliche und tierische Öle und Fette waren und sind die wichtigsten nachwachsenden Rohstoffe der chemischen Industrie. In den vergangenen zehn Jahren hat eine beträchtliche Verlagerung der oleochemischen Produktion sowohl geographisch als auch hinsichtlich des Rohstoffs stattgefunden: von Nordamerika und Westeuropa nach Südostasien bzw. von Rindertalg zu Palmöl. Es wird in den kommenden Jahren von großer Bedeutung sein, neue Ölpflanzen mit gewünschten interessanten Eigenschaften für die chemische Nutzung einzuführen und anzubauen, was auch die agrokulturelle Biodiversität erhöhen könnte. Das Problem der industriellen Nutzung von Pflanzenölen, die vorzugsweise Nahrungsmittel sind, ist mit der Entwicklung der globalen Biodieselproduktion dringlicher geworden. Im Folgenden werden die bemerkenswerten Fortschritte diskutiert, die während des letzten Jahrzehnts mit Pflanzenölen und den daraus erhaltenen oleochemischen Basischemikalien in der organischen Synthese, der Katalyse und der Biotechnologie gemacht wurden. Diese in großem Maßstab als nachwachsende Kohlenstoffquelle zur Verfügung stehenden Rohstoffe können beispielsweise über eine ω-Funktionalisierung von Fettsäuren mit inneren Doppelbindungen, die Anwendung der Olefinmetathese oder die De-novo-Synthese von Fettsäuren zu wichtigen Produkten der chemischen Industrie veredelt werden.

Oils and fats of vegetable and animal origin have been the most important renewable feedstock of the chemical industry in the past and in the present. A tremendous geographical and feedstock shift of oleochemical production has taken place from North America and Europe to southeast Asia and from tallow to palm oil. It will be important to introduce and to cultivate more and new oil plants containing fatty acids with interesting and desired properties for chemical utilization while simultaneously increasing the agricultural biodiversity. The problem of the industrial utilization of food plant oils has become more urgent with the development of the global biodiesel production. The remarkable advances made during the last decade in organic synthesis, catalysis, and biotechnology using plant oils and the basic oleochemicals derived from them will be reported, including, for example, ω-functionalization of fatty acids containing internal double bonds, application of the olefin metathesis reaction, and de novo synthesis of fatty acids from abundantly available renewable carbon sources.