[3+2]-Annulation of gem-Difluoroalkenes and Pyridinium Ylides: Access to Functionalized 2-Fluoroindolizines

A [3 + 2]-annulation of gem-difluoroalkenes and pyridinium ylides was developed employing ambient air as the sole oxidant in an open-vessel manner, affording a series of multifunctionalized 2-fluoroindolizines in moderate to good yields. In this reaction, gem-difluoroalkene acts as a C2 synthon and entirely avoids the competitive addition-elimination process, which provides facile access to 2-fluoroindolizines.

Automated summary

A novel [3+2]-annulation reaction was developed using gem-difluoroalkenes and pyridinium ylides, with ambient air as the sole oxidant in an open-vessel manner, to synthesize multifunctionalized 2-fluoroindolizines in moderate to good yields. gem-Difluoroalkene acts as a C2 synthon in this reaction, avoiding competitive addition-elimination processes and providing facile access to 2-fluoroindolizines.