Universität zu Köln

Du, Qingwei (2017). Studies in Enantioselective Transition Metal Catalysis Using Modular Phosphine-Phosphite Ligands; Gold-catalyzed Cycloaddition of 2-(1-Alkynyl)-2-alken-1-ones to Azomethine Imines. PhD thesis, Universität zu Köln.

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Abstract

The 1,3-dipolar cycloaddition, as a powerful method, was widely applied in the regio- and stereoselective synthesis of heterocycles and their ring-opened acyclic derivatives. In this work, a novel gold(I)-catalyzed 1,3-dipolar cycloaddition of 2-(1-alkynyl)-2-alken-1-ones with N,N’-cyclic azomethine imines is described, which provides a practical, efficient, regiospecific, and highly diastereoselective route to novel heterobicyclic highly substituted furo[3,4-d]pyridazines. Furthermore, enantioselective gold(I)-catalyzed cycloaddition of 2-(1-alkynyl)-2-alken-1-ones with N,N’-cyclic azomethine imines is also developed by using Taddol-derived phosphine-phosphite ligands, the so-called SchmalzPhos ligands. Under optimized reaction conditions, a variety of optically active highly substituted furo[3,4-d]pyridazines could be synthesized with excellent yields and high enantioselectivities.