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Free keywords:
Oxoassoanine; N-Acylindoline; Phenanthridone; Palladium; Crystal structure
Abstract:
Direct synthesis of the pyrrolophenanthridone scaffold was explored using an intramolecular Pd(II)-mediated coupling reaction of different N-acylindolines via C-H activation. Amaryllidaceae alkaloids of the lycorine type belong to this type. Depending on the substitution pattern of the starting materials, the pathway yielded different product patterns and yields. Introduction of electron-withdrawing substituents into the 6-position of the indoline moiety did not improve coupling. Seven N-acylindoline precursors were structurally characterized by X-ray crystallography and NMR spectroscopy. The crystal structure of the lycorine type alkaloid oxoassoanine is reported for the first time.
