Unprecedented Halide Dependence on Catalytic Asymmetric Hydrogenation of 2‐Aryl‐ and 2‐Alkyl‐Substituted Quinolinium Salts by Using Ir Complexes with Difluorphos and Halide Ligands

Abstract

A better way: Halide ligands bound to an iridium atom are the key to achieving high catalytic activity and enantioselectivity on asymmetric hydrogenation of 2-aryl- and 2-alkyl-substituted quinolinium salts. The reaction was catalyzed by a cationic dinuclear iridium(III) complex with difluorphos and chloride or bromide ligands and gave the corresponding 2-substituted 1,2,3,4-tetrahydroquinolines in high enantioselectivities (up to 95 % ee; see scheme, difluorphos=[(4,4′-bi-2,2-difluoro-1,3-benzodioxole)-5,5′-diyl]bis(diphenylphosphine)). Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.