Preparation of cationic (E)-σ-alkenyi palladium complexes having a P–O–N or a P–O–P tridentate ligand as a stabilized intermediate of palladium-catalysed stereoselective addition of methanol to acetylenes; characterisation, X-ray analysis and the reaction pathway

Abstract

Cationic (E)-σ-alkenyl palladium complexes 1 having a P–O–N or a P–O–P tridentate ligand are prepared stereoselectively from cis-PdCl₂(PN_{n= 1})[PN =o-Ph₂PC₆H₄CH₂O(CH₂)_n-2-C₅H₄N-P,N] or cis-PdCl₂(POP)[POP = Ph₂P(CH₂)₂O(CH₂)₂PPh₂-P,P] and internal alkynes in the presence of AgPF₆ and MeOH; the X-ray crystal structure of 1c is reported and a stepwise abstraction of chloride ligands for the formation of 1 is proposed.