Regiodivergent Synthesis of Densely Functionalized Indolizines via (2 + 2 + 1) Cycloaddition

A novel metal and additive free, atom-economic method for the regiodivergent synthesis of crucial 6- or 8-substituted indolizine from meta-amide-substituted pyridine and alkyne via a [2 + 2 + 1] cycloaddition is developed. The reaction proceeds through the cleavage of the carbon-carbon triple bond. The synthesized product contains an important amide group that can be further functionalized to afford biologically active compounds.