Hydrogen-Bonding Network Promoted [3+2] Cycloaddition: Asymmetric Catalytic Construction of Spiro-pseudoindoxyl Derivatives

Abstract

The enantioselective construction of a spirocyclic quaternary stereogenic carbon center at the C2 position of indole has long been an elusive problem in organic synthesis. Herein, by employing a rationally designed hydrogen-bonding network activation strategy, for the first time, 2,2'-pyrrolidinyl-spirooxindole, which is a valuable and prevalent indole alkaloid scaffold, was directly obtained through a catalytic asymmetric [3+2] cycloaddition reaction with high yields and excellent stereoselectivities.

Keywords: [3+2] cycloaddition; azomethine ylides; hydrogen bonding; quaternary carbons; spiro-pseudoindoxyl.