M. Arx, T. Mallát, A. Baiker
Dec 10, 2001
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0
Influential Citations
58
Citations
Journal
Tetrahedron-asymmetry
Abstract
Abstract The hydrogenation of 2,2,2-trifluoroacetophenones with different aryl-substituents (CF 3 , N(Me) 2 and Me) has been studied over Pt/Al 2 O 3 modified by cinchonidine, its hydrochloride or O -methyl cinchonidine. Electron-withdrawing groups increased and electron-releasing groups decreased the rate and enantioselectivity of these reactions, although steric effects (with m - or p -substituents) were also critical. The 92% e.e. achieved in the hydrogenation of 2,2,2-trifluoroacetophenone is the highest value obtained so far in this reaction using any heterogeneous catalyst system.