Catalytic Asymmetric Hydrogenation of Heteroarenes and Arenes

GRAPHICAL ABSTRACT

Abstract

A trans-chelating chiral bisphosphine, PhTRAP, allows the ruthenium-catalyzed hydrogenation of various azoles to proceed with high enantioselectivity. The PhTRAP–ruthenium catalyst transformed indoles, pyrroles, imidazoles, and oxazoles into the corresponding chiral heterocycles. Naphthalenes are also reduced with hydrogen by the chiral ruthenium catalyst, exclusively giving tetralins. Some 2-alkoxytetralins were obtained with over 90% ee from the catalytic asymmetric hydrogenation of the corresponding substituted naphthalenes.

Keywords:

• Bisphosphine
• ruthenium
• asymmetric catalysis
• hydrogenation
• azoles
• naphthalenes