Katri Lundell

Enantioselectivity of Pseudomonas cepacia and Candida rugosa lipases for the resolution of secondary alcohols: The effect of Candida rugosa isoenzymes

Abstract In this work, the lipase (Pseudomonas cepacia) (PS)- and Candida rugosa lipase (CRL)-catalyzed asymmetric deacylations of the esters of structurally different secondary alcohols were studied. Enantioselectivity in the case of lipase PS was always easily predicted according to the sizes of the substituents at the alcoholic stereocenter whereas the favored enantiomer in the case of CRL strongly depended on the structure of the racemic alcohol moiety in an ester. In the next step, commercial CRL was fractionated into its isoenzymes (A and B). The two isoenzymes A and B always gave the same enantiopreferences. This observation clearly showed that the heterogeneity of the commerical CRL was not a reason for the reversed enantioselectivity of certain substrates such as cyanohydrin, α-hydroxycarboxylic acid, and 2,2,2-trihaloethanol derivatives when compared to the selectivity observed when lipase PS was used as a catalyst.

Preparation of novel phenylfuran-based cyanohydrin esters: lipase-catalysed kinetic and dynamic resolution

A series of novel (R)-5-phenylfuran-2-yl cyanomethyl butanoates were prepared by Pseudomonas cepacia lipase- catalysed dynamic kinetic resolution in toluene. The method exploits a basic resin both for the racemization and formation of phenylfuran-based cyanohydrins and for the decomposition of acetone cyanohydrin in one-pot with enzymatic enantioselective acylation using vinyl butanoate. The lipase-catalysed methanolysis of racemic 5-phenylfuran-2-yl cyanomethyl butanoates in toluene with E 100 was shown to be usable when the corresponding (S)-butanoates are needed. Candida antarctica lipase A provided racemic cyanohydrin butanoates with quantitative chemical yields under mild conditions.

Enantiomers of ring-substituted 2-amino-1-phenylethanols by Pseudomonas cepacia lipase

Abstract The enantiomers of 2-amino-1-phenylethanols were obtained enantiomerically pure (ee > 95%) at 50% conversion by the Pseudomonas cepacia lipase-catalysed O -acylation of amino alcohols or O -deacylation of the corresponding N , O -diacylated compounds.

Preparation of the stereoisomers of 2-cyanocycloalkanols by lipase-catalysed acylation

Abstract Enantiopure (1 R ,2 R )-, (1 S ,2 S )- and (1 R ,2 S )-2-cyanocyclopentanol and -cyclohexanol isomers were prepared through the Pseudomonas cepacia lipase-catalysed acetylation of the racemic cis and trans compounds with vinyl acetate in diisopropyl ether. The quasi-irreversible nature of acylations with 2,2,2-trifluoroethyl esters is evident.