Synthesis of Indolizine Derivatives by Electrocyclization

Significance

A rapid and efficient synthesis of indolizine derivatives is presented. The silylated enyne pyridine and quinoline precursors, obtained by a Wittig-Sonogashira sequence, undergo an unexpected electrocyclic ring closure, which is triggered by a fluoride-mediated desilylation reaction under mild conditions. A plausible mechanism is proposed on the basis of analysis of deuterium labelling experiments.