The present study reports an asymmetric organocatalytic cascade reaction of oxindole derivates with α,β-unsaturated aldehydes efficiently catalyzed by simple chiralsecondaryamine. Spirooxindole-fused cyclopentanes were produced in excellent isolated yields (up to 98%) with excellent enantiopurities (up to 99% ee) and moderate to high diastereoselectivities. The synthetic utility of the protocol was
An Organocatalytic Cascade Strategy for the Enantioselective Construction of Spirocyclopentane Bioxindoles Containing Three Contiguous Stereocenters and Two Spiro Quaternary Centers
作者:Wangsheng Sun、Gongming Zhu、Chongyang Wu、Liang Hong、Rui Wang
DOI:10.1002/chem.201200478
日期:2012.5.29
A rapid and efficient organocatalyticcascade sequence for the direct construction of spirocyclopentanebioxindoles has been carried out by using a chiral squaramide catalyst in the presence of a base. This process constitutes a powerful approach to the preparation of biologically important bispirooxindoles in high enantioselectivities (see scheme).
Who owns the research process? - notes on the Belfast seminar
作者:J. Phillips、E. Blyth
DOI:10.1093/bjsw/30.4.519
日期:2000.8.1
policy makers, practitioners and service users) and a variety of outcomes. The legitimate expectations of all stakeholders raise issues of power and pose two crucial questions: first 'who controls the process of research?' (or how the politics of the research alliances are played out) and, second, 'who benefits from the research product?' (or how best can we ensure mutual reinforcement of the outcomes achieved
Construction of Tetracyclic 3-Spirooxindole through Cross-Dehydrogenation of Pyridinium: Applications in Facile Synthesis of (±)-Corynoxine and (±)-Corynoxine B
A facile and straightforward method was developed to construct the fused tetracyclic 3-spirooxindole skeleton, which exists widely in natural products. The formation of the tetracyclic 3-spirooxindole structure was achieved through a transition-metal-free intramolecular cross-dehydrogenative coupling of pyridinium, which were formed in situ by the condensation of 3-(2-bromoethyl)indolin-2-one derivatives with 3-substituted pyridines. As examples of the application of this new methodology, two potentially medicinal natural products, (+/-)-corynoxine and (+/-)-corynoxine B, were efficiently synthesized in five scalable steps.