Asymmetric transfer hydrogenation of Ethyl benzoylacetate

The reaction mixture was partitioned between diethyl ether (60 mL) and water (30 mL). The organic layer was washed with water (2 x 30mL), brine (30mL), and dried over MgS04. After concentration on a rotary evaporator, the oily residue was distilled using a Kugelrohr apparatus (120°/0.07 mbar) to yield 5.35 g (92 %) of (S)-ethyl 3-hydroxy-3-phenylpropanoate with 98 % ee. 

Gas chromatography analysis showed total consumption of starting ethyl 

These ligands and their ruthenium complexes are easy to prepare and are useful in asymmetric transfer hydrogenation of a variety of activated ketones. Table 3.4 shows a selection of substrates that can be reduced with the Ru(II)-RS02-DPEN complexes using HC02H-Et3N 5 2. 

The equivalent mthenium complex can be prepared from [RuCl2(r/ -arene)]2 precursors where / -arene = benzene, mesitylene, hexamethylbenzene. 

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