Preparation of Polyfunctional Indazoles and Heteroarylazo Compounds Using Highly Functionalized Zinc Reagents
作者:Benjamin Haag、Zhihua Peng、Paul Knochel
DOI:10.1021/ol901585k
日期:2009.10.1
available 2-chloromethylarylzinc reagents react with functionalized aryldiazoniumtetrafluoroborates providing polyfunctional indazoles. Selective metalations of these 2-aryl-2H-indazoles afford new polycyclic aromatics. The performance of a chemoselective addition of diheteroarylzincs to aryldiazonium salts allows an efficient preparation of new heterocyclic azo compounds.
Palladium-catalyzed intermolecular tandem cyclization reaction: a highly regioselective synthesis of functionalized 3H-spiro[isobenzofuran-1,3′-isochroman] scaffolds
functionalized 3H-spiro[isobenzofuran-1,3′-isochroman] scaffolds using a novel palladium-catalyzed tandem cyclization reaction is explored. During the reaction process, C–O, C–C and C–O bonds are sequentially formed in one pot viadecarboxylative allenylpalladium formation, nucleophilic attack, arylpalladium addition and intramolecular nucleophilic attack.
Zeolites are the most used catalysts worldwide in petrochemistry processes, with particular ability to stabilizecarbocations. However, the use of zeolites in organicsynthesis is still scarce. We show here that representative carboxonium-mediated organic reactions, such as the Nazarov cyclization and the tert-butylation of alcohols with tert-butyl acetate, typically performed with very strong acid