- Chemo- and Enantioselective Acyl Transfers by Lipases and Acylase I: Preparative Applications in Hydroxymethylpiperidine Chemistry
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The lipase- and acylase I-catalysed acylation of bifunctional 2- and 3-hydroxymethylpiperidines (1 and 2) and the alcoholysis of the corresponding diacylated counterparts 7 and 8 have been studied. Lipase AK from Pseudomonas fluorescens allowed the preparative-scale resolution of 7 in neat butanol at 50% conversion whereas the 3-regioisomer 8 reacted with negligible enantioselectivity (E = 7). The lipase- and acylase I-catalysed acylations of 1 and 2 in organic solvents proceeded with low enantioselectivity. On the other hand, more than 90% of 1 and 2 were transformed to amino esters 3 and 4, respectively, in a highly chemoselective O-acylation with 2,2,2-trifluoroethyl butanoate in the presence of Candida antarctica lipase A in TBME. The O-protected product 3 in the reaction mixture was readily available to another transformation at the piperidine nitrogen although 3 was not separated due to intramolecular O→N acyl migration. The tendency for acyl migration was much less significant in the case of 4.
- Lundell, Katri,Lehtinen, Petka,Kanerva, Liisa T.
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p. 790 - 796
(2007/10/03)
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- ENZYME-MEDIATED ENANTIOSELECTIVE ACYLATION OF SECONDARY AMINES IN ORGANIC SOLVENTS
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Porcine pancreatic lipase (PPL) and lipase Amano P catalyze the enantioselective acylation of cyclic 1,2- and 1,3-amino alcohol derivatives in organic solvents.The enantiomeric excesses (ee's) were shown to depend on the enzyme, reaction time, temperature and type of substrate.
- Asensio, Gregorio,Andreu, Cecilia,Marco, J. Alberto
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p. 4197 - 4198
(2007/10/02)
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