title: Green and efficient synthesis of sulfonamides catalyzed by nano-Ru/Fe(3)O(4).
abstract: The environmentally benign synthesis of carbon-nitrogen bonds continues to be an active and challenging field of chemical research. Here, a novel, environmentally benign method for the direct coupling of sulfonamides and alcohols is described. Despite the importance of sulfonamide derivatives as intermediates in drug synthesis, till now such transformations are rarely known. For the first time a domino dehydrogenation-condensation-hydrogenation sequence of alcohols and sulfonamides has been realized in the presence of a nanostructured catalyst. The magnetic property of the catalyst system allows for convenient isolation of the product and efficient recycling of the catalyst. A variety of coupling reactions of benzylic alcohols and sulfonamides including various heterocycles were successfully realized, often with >80% isolated yield. Advantageously, only one equivalent of the primary alcohol is consumed in the process. Mechanistic investigations of the competitive reactions of benzyl alcohol and d(7)-benzyl alcohol with p-toluenesulfonamide revealed a kinetic isotope effect (k(H)/k(D)) of 2.86 (+/-0.109) for the dehydrogenation of benzyl alcohol and 0.74 (+/-0.021) for the hydrogenation of N-benzylidene-p-toluenesulfonamide intermediate, which suggests dehydrogenation of the alcohol to be the rate determining step.
authors.affiliation: Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Strasse 29a, 18059 Rostock, Germany.
authors.forename: Feng
authors.initials: F
authors.lastname: Shi
authors.forename: Man Kin
authors.initials: MK
authors.lastname: Tse
authors.forename: Shaolin
authors.initials: S
authors.lastname: Zhou
authors.forename: Marga-Martina
authors.initials: MM
authors.lastname: Pohl
authors.forename: Jörg
authors.initials: J
authors.lastname: Radnik
authors.forename: Sandra
authors.initials: S
authors.lastname: Hübner
authors.forename: Klaus
authors.initials: K
authors.lastname: Jähnisch
authors.forename: Angelika
authors.initials: A
authors.lastname: Brückner
authors.forename: Matthias
authors.initials: M
authors.lastname: Beller
mesh_terms: D000438:Alcohols / Q000737:chemistry; D002384:Catalysis; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D012428:Ruthenium / Q000737:chemistry*; D013449:Sulfonamides / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000438:Alcohols; D013449:Sulfonamides; D012428:Ruthenium; D052203:Ferrosoferric Oxide