Enzymatic resolution of rac-1,1-dimethyl-1-sila-cyclohexan-2-ol by ester hydrolysis or transesterification using a crude lipase preparation of Candida cylindracea

Abstract

Summary. rac-2-Acetoxy-1,1-dimethyl-1-sila-cyclohexane (rac-2) was synthesized by esterification of rac-1, 1-dimethyl-1 ~sila-cyclohexan-2-ol (rac-1) with acetic anhydride. Enantioselective hydrolysis of rac-2 in aqueous solution, catalysed by a crude Iipase preparation of Candida cylindracea (EC 3.1.1.3), led to the formation of (S)-1 (95% ee). Enantioselective transesterification of rac-1 with triacetin in isooctane, catalysed by the same enzyme preparation, yielded (S)-2 (95% ee), which was separated by chromatography from non-reacted (R)~1 (96% ee). Recrystallization led to an improvement of the enantiomeric purity of (R)-1 and (S)-1 up to >98% ee. Thus the enantiomers of rac-1 were prepared (100 mg scale) with high enantiomeric purities by the use of two different types of enzyme-catalysed reaction.

Enantioselective microbial reduction of 1,1-dimethyl-1-sila-cyclohexan-2-one with growing cells of the yeast Kloeckera corticis (ATCC 20109)

“…The results decribed in this paper and elsewhere [1][2][3][4][5][6][7][8][9]12] demonstrate that enantioselective biotransformations may be useful for the synthesis of optically active organosilicon compounds on a preparative scale.…”

“…The absolute configuration and enantiomeric purity of (R)-2 were determined, after deriva tiza tion with ( R )-a-methoxy-a-trifluoromethyl-phenylacetyl chloride Both enantiomers of 2 were recently prepared in high enantiomeric purity via an enzymatic resolution of rac-2 [12]: ( R )-2 was obtained by enantioselective transesterification of rac-2 with triacetin in isooctane using a crude lipase preparation of Candida cylindracea (E.C. 3.1.1.3), and the corresponding antipode (S)-2 was prepared by enantioselective hydrolysis of rac-2-acetoxy-1,1-dimethyl-1-silacyclohexane in aqueous solution using the same enzyme preparation.…”

Production of extracellular lipase by Candida cylindracea CBS 6330

“…This property can be used to enrich fats from natural sources in essential fatty acids giving an increase in their utility and value [5]. Also very important is the application of lipases in the separation of racemic mixtures in the optic isomers production [6].…”

Organosilicon Biotechnology

“…7 The general structure of a silatrane ol via two different routes (Fig. 9) [59]. Initially the racemic alcohol was transformed into the racemic acetate ester using acetic anhydride.…”