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Total synthesis of the putative structure of stemonidine: the definitive proof of misassignment
Francisco Sánchez-Izquierdo1, Pilar Blanco, Félix Busqué
1Universitat Autonoma de Barcelona, Departament de Química, 08193 Bellaterra, Spain.
Abstract:
[structure: see text] The total synthesis of the putative structure of the Stemona alkaloid stemonidine has been completed. The key transformations include a 1,3-dipolar cycloaddition of a chiral nitrone derived from (S)-prolinol and a spirolactonization process involving the generation of the critical stereocenter. The NMR data of the synthetic material do not match those reported for the natural product. It is concluded that the structure assigned to stemonidine is incorrect, and it must be reassigned as stemospironine.
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