New pseudohalide ligands in Ru-catalyzed olefin metathesis A robust, air-activated iminopyrrolato catalyst

Abstract

Reaction of the Grubbs catalyst RuCl 2 (PCy 3 ) 2 (CHPh) (1) with lithium 2-[(2,6-diisopropylphenyl)imino]pyrrolide·Et 2 O (LiNN′·Et 2 O) gives alkylidene complex 5, containing a chelating, σ-bound iminopyrrolato unit. The structure of 5 is confirmed by X-ray crystallography. Treatment of 5 with pyridine generates RuCl(NN′)(py) 2 (CHPh) (6) via displacement of PCy 3 . Complex 5 effects ring-closing metathesis in air, displaying high reactivity relative to 6.Key words: ruthenium, alkylidene, metathesis, pyrrolimine, iminopyrrolato.