Imidazolinium Salts as Catalysts for the Ring-Opening Alkylation of meso Epoxides by Alkylaluminum Complexes

[reaction: see text] Imidazolinium salts and their N-heterocyclic carbene (NHC) derivatives catalyze the alkylation of a variety of meso epoxides in the presence of triethylaluminum (yield = 70-90%), under mild conditions. Imidazolinium salts are better catalysts than their NHC derivatives but can lead to dimerization side reactions under extended reaction time. Preformed NHC.AlEt(3) complexes and Wanzlick-type olefins, which are dimers of free NHCs, are also catalysts for this reaction.