A series of metal-catalyzed processes are presented, in which carboxylic acids act as sources of either carbon nucleophiles or electrophiles, depending on the catalyst employed, the mode of activation, and the reaction conditions. A first reaction mode is the addition of carboxylic acids or amides over C-C multiple bonds, giving rise to enol esters or enamides, respectively. The challenge here is to control both the regio- and stereoselectivity of these reactions by the choice of the catalyst system. Alternatively, carboxylic acids can efficiently be decarboxylated using new Cu catalysts to give aryl-metal intermediates. Under protic conditions, these carbon nucleophiles give the corresponding arenes. If carboxylate salts are employed instead of the free acids, the aryl-metal species resulting from the catalytic decarboxylation can be utilized for the synthesis of biaryls in a novel cross-coupling reaction with aryl halides, thus replacing stoichiometric organometallic reagents. An activation with coupling reagents or simple conversion to esters allows the oxidative addition of carboxylic acids to transition-metal catalysts under formation of acyl-metal species, which can either be reduced to aldehydes, or coupled with nucleophiles. At elevated temperatures, such acyl-metal species decarbonylate, so that carboxylic acids become synthetic equivalents for aryl or alkyl halides, e.g., in Heck reactions.

The glass-transition-, melting, and onset decomposition temperatures of a series of tailored polymethacrylates and polyacrylates are systematically investigated. Application fi elds of the investigated polymers include coatings, adhesives, textile, paper, cosmetics, electronics, lubricants, fuel additives, and oil-fi eld or construction chemicals. The present study focuses on linear alkyl, branched alkyl, and amino, as well as ether polymethacrylates and polyacrylates. Novel polymers are introduced with branched C9, C13, C17, and C21 ester, Lupragen, or glycopyranoside ester groups. The thermal characteristics of the novel polymers are analyzed and placed into the context of the thermal data of known polymers fi tting into the homologous series. General trends providing a comprehensive and concise overview of the determined thermal properties are derived. Structureproperty relationships are established and a detailed physicochemical rationale is provided. The study may even allow for a rapid empirical estimation of thermal data of not yet assessed polymer systems.

The use of aryl triflates as reaction partners in a palladium-catalyzed domino direct arylation/N-arylation provides a great advantage due to the availability of starting materials. Furthermore, it allows expedient access to biologically interesting benzo[c]phenanthridine alkaloids.

A rational catalyst development based on mechanistic and spectroscopic investigations led to the discovery of a new protocol for catalytic hydroamidation reactions that draws on easily available ruthenium trichloride trihydrate (RuCl 3 ·3 H 2 O) as the catalyst precursor instead of the previously employed, expensive bis(2-methylallyl)(1,5-cyclooctadiene)ruthenium(II). This practical and easy-to-use protocol dramatically improves the synthetic applicability of Ru-catalyzed hydroamidations. The catalyst, generated in situ from rutheniumA C H T U N G T R E N N U N G (III) chloride hydrate, tri-n-butylphosphine, 4-(dimethylamino)-pyridine and potassium carbonate, effectively promotes the addition of secondary amides, lactams and carbamates to terminal alkynes under formation of (E)-anti-Markovnikov enamides. The scope of the new protocol is demonstrated by the synthesis of 24 functionalized enamide derivatives, among them valuable intermediates for organic synthesis.

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