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20.5.11.1.2.1.2 Variation 2: Heterogeneous Catalytic Asymmetric Hydrogenation of 2-Oxoalkanoates

DOI: 10.1055/sos-SD-020-01122

Chemler, S. R.; Zabawa, T. P.Science of Synthesis, (2007201216.

The enantioselective hydrogenation of alkyl 2-oxoalkanoates with a heterogeneous cinchona-modified platinum/alumina catalyst system is known as the Orito reaction.[‌102‌‌104‌] Heterogeneous catalysts offer the benefit of catalyst recovery from the reaction medium by a simple filtration procedure. Several cinchona modifiers are shown in Scheme 14. Reduction of α-oxo esters using the cinchonidines 35 provides the (R)-α-hydroxy ester while the cinchonines 36 provide the (S)-α-hydroxy ester.

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