Desymmetrization of meso-methylenecyclopropanes by a palladium-catalyzed asymmetric ring-opening bis(alkoxycarbonylation) reaction
摘要:
Desymmetrization of various meso-methylenecyclopropanes was accomplished by a palladium-catalyzed asymmetric ring-opening bis(alkoxycarbonylation) reaction employing a chiral bioxazoline ligand. The reaction proceeded smoothly in the presence of copper(I) triflate under carbon monoxide and oxygen at ambient pressure to give the corresponding optically active alpha-methyleneglutarates with up to 60% ee. Desymmetrization of protected meso-(3-methylenecyclopropane-1,2-diyl)dimethanols was also carried out to give enantioenriched highly oxygen-functionalized alpha-methyleneglutarates. (C) 2014 Elsevier Ltd. All rights reserved.