Ru‐catalyzed Asymmetric Hydrogenation of Aryl Ketones Using Tetrazole Derived NH₂‐hybrid Ligand

Abstract

Readily available chiral hybrid NH 2 /tetrazole ligand [(S)-TEA, 1] in combination with Ru-BINAP or Ru-DIOP complexes catalyzes the asymmetric hydrogenation of a number of simple ketones with moderate enantioselectivity (up to 72% ee). The tetrazole functionality results in reversal of the typically observed chiral-induction for related systems and allows for hydrogenation to be uncharacteristically conducted in (non-protic) THF solvent. The observed catalyst performance is sensitive to the reaction conditions employed and the particular compounds involved. The origins of such features are considered to derive from the added functionality provided by the tetrazole moiety in 1, which due to its modular nature provides a good basis for further development.