Pyrazolyl-substituted Phosphorus(III) compounds in synthesis

Abstract

• Alternative synthetic methods in phosphorus chemistry. • Pyrazolyl-substituted phosphanes reveal a versatile potential in synthetic chemistry. • Pyrazolyl-substituents are amenable, potentially recyclable leaving groups. • Pyrazolylphosphanes are feasible, easy to handle and sustainable alternative to the related chloro-phosphanes. This Minireview aims to provide an overview on the chemistry of pyrazolyl-substituted phosphorus compounds with focus on their preparation and especially on their synthetic application. The majority of these compounds, in particular tripyrazolylphosphanes, are used as multidentate ligands in coordination chemistry. However, these compounds bear a versatile potential in e.g. condensation reactions (or solvolysis), salt metathesis reactions, deoxygenation reactions or P–P bond formation reactions ( via condensation or P–N/P–P bond metathesis), in which the respective pyrazolyl-substituents act as amenable leaving group. The reactions involving pyrazolylphosphanes typically run under mild conditions, are often very selective and the released pyrazole can be potentially recycled, rendering these compounds a more feasible and sustainable alternative to the related chloro-phosphanes.