Pyrido-anellated 1,3-azaphospholes-current state and future challenges

A short overview of the syntheses, properties and some reactions of pyrido-anellated 1.3-azaphospholes is presented. Except for 2-phosphaindolizines, which have been intensively studied with respect to syntheses, electrophilic substitution and cycloadditions, this is a class of compound that has still been only sparingly investigated. Preliminary results and hints as to possible perspectives are included to encourage further research on these novel P,N hybrid ligands.