Asymmetric copper-catalyzed cyclopropanation of trisubstituted and unsymmetrical cis-1, 2-disubstituted olefins: modified bis-oxazoline ligands

RE Lowenthal, S Masamune

Index: Lowenthal, Richard E.; Masamune, Satoru Tetrahedron Letters, 1991 , vol. 32, # 50 p. 7373 - 7376

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Citation Number: 299

Abstract

Abstract The Cu (I) complexes of new bis-oxazolines (3–7) prepared from the corresponding amino alcohols and malono-bis-imidate exhibit high enantioselectivity of up to 94% ee in the catalytic cyclopropanation of trisubstituted and unsymmetrical cis-1, 2-disubstituted olefins. New diazoacetate reagents have also been developed giving high trans/cis ratios of up to 99: 1 trans.