Syntheses and properties of phosphino- and phosphinatopyrroles

Abstract

The syntheses of P—N bonded pyrrolyl- and 2,5-dimethylpyrrolylphosphines [Formula: see text] (x = 0–2) and the oxy derivatives py3PO and (Me2py)2P(O)Cl by the reaction of potassium pyrrolide or 2,5-dimethylpyrrolide with an appropriate chlorophosphine or with POCl3 are described. Molecular structures were inferred from spectroscopic data. The P—N bonded phosphines are stable to solvolytic attack by water or alcohols and do not undergo insertion reactions with CS2, but they are oxidised by oxygen and suffer nucleophilic displacement of the azole moiety by strong base. The Lewis acid BCl3 cleaves the P—N bond and CH3I reacts with only one member, [Formula: see text] to form a phosphonium salt. Hindered rotation about the P—N bond was detected in the (2,5-dimethylpyrrolyl)phosphine series, but not among the corresponding oxy derivatives. The nature of the P—N bond and trends in the basicity of the phosphorus atom are discussed.