Straightforward Access to Enantioenriched <i>cis</i>-3-Fluoro-dihydroquinolin-4-ols Derivatives via Ru(II)-Catalyzed-Asymmetric Transfer Hydrogenation/Dynamic Kinetic Resolution

Abstract

Herein we report a practical method for the asymmetric transfer hydrogenation/dynamic kinetic resolution of N-Boc 3-fluoro-dihydrotetrahydroquinolin-4-ones into the corresponding cis-fluoro alcohols in 70–96% yields, up to 99:1 diastereomeric ratio (dr) and up to >99% ee (enantiomeric excess) by using the ruthenium complex Ts-DENEB and a formic acid/triethylamine (1:1) mixture as the hydrogen donor under mild conditions.

Keywords

• asymmetric catalysis
• reduction
• fluorine
• hydrogen transfer
• ruthenium