Synthesis of Spiro[indole-3,3'-pyrrolidine]-2'-(thi)ones

J Org Chem. 2023 Jan 20;88(2):1093-1106. doi: 10.1021/acs.joc.2c02561. Epub 2022 Dec 28.

Abstract

Spiro[indole-3,3'-pyrrolidine]-2'-ones were synthesized via one-pot chloroformylation-dearomatizing spirocyclization of tryptamine derivatives. Moreover, the "thio" equivalent spiro[indole-3,3'-pyrrolidine]-2'-thiones, for which the synthesis and properties were previously unreported, were synthesized. The procedures are easily implemented, have a broad scope, and are transition-metal-free and cheap. To demonstrate the utility of the synthetic methodology, the spiro[indole-3,3'-pyrrolidine]-2'-ones were converted into heterocyclic scaffolds, such as an optically active spiroindoline and spirooxindole.