B2pin2-Mediated Cascade Cyclization/Aromatization Reaction: Facial Access to Functionalized Indolizines

Herein, a B2pin2-mediated radical cascade cyclization/aromatization reaction of enaminone with pyridine is described. This strategy provides a practical way for the construction of valuable functionalized indolizines under metal-, external oxidant-, and base-free conditions, which could be compatible with various kinds of functional groups, such as halogen, pi-system, heterocycle, ferrocenyl, etc. A preliminary mechanism investigation indicated that the pyridine-boryl radical formed in situ triggered the reaction to occur.

Automated summary

This paper describes a B2pin2-mediated radical cascade cyclization/aromatization reaction of enaminone with pyridine, providing a practical way for constructing valuable functionalized indolizines under metal-, external oxidant-, and base-free conditions. The reaction is compatible with various functional groups and is triggered by the in situ formation of a pyridine-boryl radical.