Ruthenium catalyzed transfer hydrogenation from isopropanol to ketones has proven to be an efficient method for the preparation of secondary alcohols.  We have constructed optically active β-amino alcohols as a library of chiral auxiliaries based on the natural terpenes, limonene and carene.  Naturally occurring terpenes such as limonene, carene and pinene are inexpensive compounds that are commercially available.  A variety of these limonene and carene derived amino alcohols have been coordinated to (p-CymeneRuCl₂)₂ dimer complexes and screened for their catalytic abilities in the asymmetric transfer hydrogenation of a selection of ketones.  This novel line of ruthenium-amino alcohol catalysts has yielded optically active secondary alcohols with up to 99% conversion and 71% enantiomeric excess.

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