Phosphirane-Enabled\nSynthesis of Aromatic 1<i>H</i>‑1,2-Azaphospholes\nand Phosphinines

Aromatic heteroarenes are essential\ncomponents of numerous\nvaluable\nmolecules. Herein we present a simple and effective route to access\naromatic 1<i>H</i>-1,2-azaphospholes and phosphinines. This\nmethod utilizes the ring tension of phosphiranes to convert simple\nβ-chloroethylphosphane and alkynyl imines into these valuable\ncompounds. The nucleophilic addition of the phosphiranide complex\nto alkynyl imines results in phosphiranes <b>3</b>, which transform\ninto 1<i>H</i>-1,2-azaphospholes under mild conditions.\nThe skeletal editing of 1,2-azaphospholes into phosphinine derivatives\nwas accomplished through a cascade process involving a [4 + 2] cycloaddition\nand the elimination of a nitrogen moiety.