Imidazolium-oxazoline salts in ruthenium-catalyzed allylic substitution and cross metathesis of formed branched isomers

Article abstract of DOI:10.1002/ejic.201000718

Imidazolium-oxazoline chlorides have been prepared from chloroacetonitrile and used to generate bidentate mixed NHC-oxazoline ligands for ruthenium-catalyzed substitution of cinnamyl chloride by phenols. These ligands associated to [RuCp*(MeCN)₃][PF₆] promote allylic substitution reactions at room temperature with high regioselectivity in favour of the branched isomers giving terminal alkenes. These allylic ethers have been involved in further ruthenium-catalyzed cross metathesis reactions with electron-deficient olefins to give unsaturated esters and aldehydes. NHC-oxazoline ligands associated to the Cp*Ru^II moiety generate catalysts that orientate the nucleophilic allylic substitution of cinnamyl chloride by phenols towards the regioselective formation of branched products, which, on reaction with Hoveyda(II) catalyst, lead to cross metathesis, and unsaturated functional compounds.