ASYMMETRIC CATALYSIS .52. RHODIUM CATALYZED ENANTIOSELECTIVE TRANSFER HYDRATION OF C=C DOUBLE-BONDS WITH THE HCO2H/NET3 SYSTEM AS A HYDROGEN SOURCE

Enantioselective rhodium catalyzed transfer hydrogenation with a mixture of formic acid and triethylamine as hydrogen source was used for the asymmetric hydrogenation of α,β-unsaturated carboxylic acids, esters and ketones, and of olefins. In certain cases, the reaction rate and the enantioselectivity is slightly higher than in the reduction with gaseous hydrogen, but in general the results are similar. In the transfer hydrogenation of 3-methyl-2-cyclopentenone only the CC double bond is reduced. Double bond migration occurs as a side-reaction in olefins. © 1990.