Route C. Synthesis and Enantioselective Hydrogenation of Keto Ester

Route C Synthesis and Enantioselective Hydrogenation of Keto Ester 5 

In the most recent of all routes discussed, HPB ester was synthesized in only three steps (Fig. 3) [2 a]. In this variant, a different ketone intermediate was synthesized in one step from the low cost acetophenone and diethyl oxalate in high yield. For the reduction, a similar catalytic system as described for route C was used. However, the maximum ee values and the catalyst activity were some- 

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