New Strategies for N-Heterocyclic Carbenes Catalyzed Annulations

ISBN-13: 9789811028984 / Angielski / Twarda / 2016 / 123 str.

Xiangyu Chen

Opis

This thesis focuses on NHC-catalyzed annulation of nitroalkenes, enals and α,ss-unsaturated carboxylic acids. (4) The readily available α,ss-unsaturated carboxylic acids were first successfully employed to generate the α,ss-unsaturated acyl azolium intermediates by using NHC for the enantioselective [3+2] and [3+3] annulations.

Spis treści

Introduction.- NHC-catalyzed Annulations of Nitroalkenes.- NHC-catalyzed Enantioselective Annulations of Enals.- NHC-catalyzed Enantioselective Annulations of α,β-unsaturated Carboxylic Acids.- Experimental Part.- Research Summary.

Blurb

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