Stereochemical Investigation on Asymmetrically Modified Raney Nickel Catalyst. Mode of Interaction between Modifying Reagent and Substrate in the Enantioface-differentiating Process
The mode of enantioface-differentiating hydrogenation with asymmetrically modifiedRaneynickel (MRNi) was investigated by using various sorts of modifying reagents and substrates. The optical yields (O.Y.) of the hydrogenation of methyl acetoacetate over MRNi for different modifying reagents occured in the following order: (Remark: Graphics omitted.), (Remark: Graphics omitted.). The hydrogenation
Enantioselectivity reversal: Candida rugosa lipase (CRL) exhibits unexpected enantioselectivity (i.e., S selectivity, E=58) towards 4‐(tert‐butoxycarbonylamino)butan‐2‐ol. A molecular modeling study suggests that the formation of a hydrogen bond between the Ser450 residue and the carbamate nitrogen atom is essential for the observed selectivity.