3-(2-Isocyanoethyl)indole: A Versatile Reagent for Polycyclic Spiroindoline Synthesis

Polycyclic spiroindolines are the basic skeletons of large families of indole alkaloids that exhibit a broad spectrum of biological and pharmacological activities. The past seven years have seen impressive developments in the construction of polycyclic spiroindolines enabled by 3-(2-isocyanoethyl)indole-based cascade reactions. We herein give a brief summary on this evolution and highlight our contributions in this field. 1 Introduction 2 Cascade Reactions Involving Nitrilium Ion Intermediates 3 Cascade Reactions Involving Ketenimine Intermediates 4 Conclusion and Outlook