三亚乙基二胺催化了前所未有的远程烯烃/异构化/[4 + 2] -环加成反应，以合成螺环氧化吲哚六氢吲哚。

Trienamine catalysed unprecedented remote olefin / isomerisation/[4 + 2]-cycloaddition reaction to access spirooxindole hexahydroindoles.

作者信息

Prasad Madavi S, Sivaprakash Murugesan, Bharani Sankar, Chowhan L Raju

机构信息

Asymmetric Synthesis and Catalysis Laboratory, Department of Chemistry, Central University of Tamil Nadu (CUTN), Tiruvarur-610 005, India.

School of Applied Material Sciences, Centre for Applied Chemistry, Central University of Gujarat, Sector-30, Gandhinagar-382030, Gujarat, India.

出版信息

Org Biomol Chem. 2023 Feb 1;21(5):945-949. doi: 10.1039/d2ob02228a.

DOI:10.1039/d2ob02228a

PMID:36606372

Abstract

Herein, for the first time, we report the asymmetric synthesis of an unexpected stereoisomer of spirohexahydroindole a trienamine-catalysed remote olefin / isomerisation/[4 + 2]-cycloaddition reaction. The reaction afforded a vast library of aesthetically pleasing spirooxindole hexahydroindole scaffolds with exceptional enantio- and diastereo-selectivities (up to 95% yield, 99% ee and >99 : 1 dr). In addition, we demonstrated the synthetic transformation of enantiomerically pure spirooxindole hexahydroindoles to synthesize alkyl homologated spirooxindole hexahydroindole and fluoro-pyranooctahydroindole moieties with four and seven contiguous stereocenters, respectively, in excellent yield and selectivities. We have also demonstrated the evidence for the proposed pathway through NMR investigations.

摘要

在此，我们首次报道了通过三烯胺催化的远程烯烃/异构化/[4 + 2] -环加成反应不对称合成螺六氢吲哚的一种意外立体异构体。该反应提供了大量具有出色对映体和非对映体选择性（产率高达95%，对映体过量值高达99%，非对映体比例>99:1）的美观的螺氧化吲哚六氢吲哚骨架产物库。此外，我们展示了对映体纯的螺氧化吲哚六氢吲哚的合成转化，分别以优异的产率和选择性合成了具有四个和七个连续立体中心的烷基同系化螺氧化吲哚六氢吲哚和氟代吡喃八氢吲哚部分。我们还通过核磁共振研究证明了所提出途径的证据。