Synlett

Enantioselective synthesis of chromanes by iridium-catalyzed asymmetric hydrogenation of 4H-chromenes

C Valla, A Baeza, F Menges, A Pfaltz

Index: Valla, Carine; Baeza, Alejandro; Menges, Frederik; Pfaltz, Andreas Synlett, 2008 , # 20 p. 3167 - 3171

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Citation Number: 13

Abstract

Abstract Iridium complexes of chiral oxazoline-based P, N-ligands proved to be efficient catalysts for the enantioselective hydrogenation of 2-aryl-and 2-alkyl-4H-chromenes. The best results were obtained with a ligand derived from threonine (ThrePHOX), which induced ee values of 95% to> 99% in the hydrogenation of 2-methyl-, 2-cyclohexyl-and various 2-aryl- substituted chromenes.