Enzymatic Hydrolysis and Esterification Reactions

In 2003, Kanerva s group reported the preparation of novel (l )-furyl-benzothiazole-based cyanohydrin acetates from the corresponding furan- 

When the preceding conditions for the enantioselective synthesis of cyanohydrin acetates via DKR were applied to aliphatic substrates, only a kinetic resolution was observed. However, Hanefeld s group has shown that, by 

In 2005, Bornscheuer s group studied the DKR of acyloins, which constitute important building blocks in organic synthesis e.g. for the total synthesis of epothilones). No combination of base and solvent was found that could selectively racemise the acyloins or the corresponding esters under the conditions needed for a DKR. In contrast to bases, an acidic resin such as Amberlyst 15 was found to racemise the acyloins selectively in n-hexane and in water. Unfortunately, the acidic resin deactivated the lipase Candida antarctica lipase 

CAL-B), preventing a one-pot DKR. However, an efficient DKR was made possible by the spatial separation of lipase and ion exchanger, with enzymatic transesterification and resin-catalysed racemisation taking place simultaneously in two compartments connected by a pump loop. In these 

The enzyme-catalysed hydrolysis of SchifiF bases derived from racemic amino acid esters and aromatic aldehydes was studied by Parmar et al. The L-amino acid precipitated out from the solution as the reaction progressed and the liberated aldehyde and unhydrolysed o-ester remained in solution. 

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