Goossen, LJ (Lukas J)
J Am Chem Soc. 2012 Jun 8;: 22681310
Department of Organic Chemistry, Technische Universität Kaiserslautern , Erwin-Schrödinger-Str. Geb. 54, 67663 Kaiserslautern, Germany.
Decarboxylative Chan-Evans-Lam-type couplings are presented as a new strategy for the regiospecific construction of diaryl and alkyl aryl ethers starting from easily available aromatic carboxylic acids. They allow converting various aromatic carboxylate salts into the corresponding aryl ethers by reaction with alkyl orthosilicates or aryl borates, under aerobic conditions in the presence of silver carbonate as the decarboxylation catalyst and copper acetate as the cross-coupling catalyst.
Chemistry. 2012 Feb 6;18 (6):1577-81 22238176
Oxidative trifluoromethylation of arylboronates with shelf-stable potassium (trifluoromethyl)trimethoxyborate.
Fachbereich Chemie-Organische Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Strasse Geb. 54, 67663 Kaiserslautern, Germany.
Most cited papers:
Institut für Organische Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Strasse, Building 54, D-67663 Kaiserslautern, Germany. firstname.lastname@example.org
We present a safe and convenient cross-coupling strategy for the large-scale synthesis of biaryls, commercially important structures often found in biologically active molecules. In contrast to traditional cross-couplings, which require the prior preparation of organometallic reagents, we use a copper catalyst to generate the carbon nucleophiles in situ, via decarboxylation of easily accessible arylcarboxylic acid salts. The scope and potential economic impact of the reaction are demonstrated by the synthesis of 26 biaryls, one of which is an intermediate in the large-scale production of the agricultural fungicide Boscalid.
FB Chemie-Organische Chemie, TU Kaiserslautern, Erwin-Schrödinger-Strasse Geb. 54, 67663 Kaiserslautern, Germany. email@example.com
Biaryl and Aryl Ketone Synthesis via Pd-Catalyzed Decarboxylative Coupling of Carboxylate Salts with Aryl Triflates.
FB Chemie-Organische Chemie, TU Kaiserslautern, Erwin-Schroedinger-Strasse Geb. 54, 67663 Kaiserslautern (Germany), Fax:(+49) 631-205-3921.
A bimetallic catalyst system has been developed that for the first time allows the decarboxylative cross-coupling of aryl and acyl carboxylates with aryl triflates. In contrast to aryl halides, these electrophiles give rise to non-coordinating anions as byproducts, which do not interfere with the decarboxylation step that leads to the generation of the carbon nucleophilic cross-coupling partner. As a result, the scope of carboxylate substrates usable in this transformation was extended from ortho-substituted or otherwise activated derivatives to a broad range of ortho-, meta-, and para-substituted aromatic carboxylates. Two alternative protocols have been optimized, one involving heating the substrates in the presence of Cu(I)/1,10-phenanthroline (10-15 mol %) and PdI(2)/phosphine (2-3 mol %) in NMP for 1-24 h, the other involving Cu(I)/1,10-phenanthroline (6-15 mol %) and PdBr(2)/Tol-BINAP (2 mol %) in NMP using microwave heating for 5-10 min. While most products are accessible using standard heating, the use of microwave irradiation was found to be beneficial especially for the conversion of non-activated carboxylates with functionalized aryl triflates. The synthetic utility of the transformation is demonstrated with 48 examples showing the scope and limitations of both protocols. In mechanistic studies, the special role of microwave irradiation is elucidated, and further perspectives of decarboxylative cross-couplings are discussed.
Copper-catalyzed trifluoromethylation of aryl iodides with potassium (trifluoromethyl)trimethoxyborate.
Fachbereich Organische Chemie, TU-Kaiserslautern, Kaiserslautern, Germany.
Potassium (trifluoromethyl)trimethoxyborate is introduced as a new source of CF(3) nucleophiles in copper-catalyzed trifluoromethylation reactions. The crystalline salt is stable on storage, easy to handle, and can be obtained in near-quantitative yields simply by mixing B(OMe)(3), CF(3)SiMe(3), and KF. The trifluoromethylation reagent allows the conversion of various aryl iodides into the corresponding benzotrifluorides in high yields under mild, base-free conditions in the presence of catalytic quantities of a Cu(I)/1,10-phenanthroline complex.
Fachbereich Chemie, Technische Universitat Kaiserslautern, Erwin-Schroedinger-Strasse, D-67663 Kaiserslautern, Germany.
An effective protocol has been developed that allows the smooth protodecarboxylation of diversely functionalized aromatic carboxylic acids within 5-15 min. In the presence of at most 5 mol % of an inexpensive catalyst generated in situ from copper(I) oxide and 1,10-phenanthroline, even nonactivated benzoates were converted in high yields and with great preparative ease.
Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany. firstname.lastname@example.org
Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany. email@example.com
Enantioselective Rh-catalyzed hydrogenation of vinyl carboxylates with monodentate phosphite ligands.
Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim/Ruhr, Germany. firstname.lastname@example.org
[reaction: see text] Alkyl-substituted vinylcarboxylates, which normally show poor enantioselectivity in Rh-catalyzed hydrogenation with traditional chiral diphosphines, undergo highly enantioselective reactions with BINOL- and carbohydrate-based monophosphite ligands.
Ru-catalyzed anti-Markovnikov addition of amides to alkynes: a regio- and stereoselective synthesis of enamides.
Regiocontrolled Ru-catalyzed addition of carboxylic acids to alkynes: practical protocols for the synthesis of vinyl esters.
Max Planck Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany. email@example.com
The catalytic activity of commercially available, air and water stable ruthenium complexes in the addition of carboxylic acids to terminal alkynes was found to be drastically enhanced by the addition of small quantities of base. Moreover, the regioselectivity of the reaction can be controlled by the choice of the base so that both the Markovnikov (Na2CO3) and the anti-Markovnikov products (DMAP) are now easily accessible in excellent selectivities.