New Strategies for N-Heterocyclic Carbenes Catalyzed AnnulationsThis thesis focuses on NHC-catalyzed annulation of nitroalkenes, enals and ‘,’-unsaturated carboxylic acids. (1) NHCs were found to be efficient catalysts for the [4+2] annulation of ‘-substituted nitroalkenes. The scope of Rauhut’Currier reaction was successfully extended to the most challenging ‘-substituted alkenes by this method; (2) Enals were successfully used for [4+2] annulations with azodicarboxylates catalyzed by NHC via ‘-addition. Highly enantiopure tetrahydropyridazinones and ‘-amino acid derivatives could be easily prepared by subsequent transformations of the resulting dihydropyridazinones. (4) The readily available ‘,’-unsaturated carboxylic acids were first successfully employed to generate the ‘,’-unsaturated acyl azolium intermediates by using NHC for the enantioselective [3+2] and [3+3] annulations. ISBN: 9789811028984, 9811028982
