Resolution of racemic sterically hindered secondary alcohols via enzymatic alcoholysis of their esters. The first enzymatic preparation of optically pure 2,2,2-trifluoro-1-(9-anthryl)ethanols
✍ Scribed by Eleonora Shkolnik; Arie L. Gutman
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 804 KB
- Volume
- 2
- Category
- Article
- ISSN
- 0968-0896
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✦ Synopsis
An approach has been developed which exploits the non aqueous enzymatic alcoholysis reaction for resolution of racemic stcrically hindered secondary alcohols. The method was used effectively in the first enzymatic preparation of both enantiomers of the title compound via porcine pancreatic lipase catalysed alcoholysis of its butyrate ester. A considerable enhancement of the reaction rate was achieved by dispersion of the powdered enzyme preparation on aluminium oxide. A facile procedure was developed for separating the (R)-alcohol product from the unreactive (S)-butyrate ester and for the hydrolysis of the latter into the ($)-alcohol. The preparative usefulness of the resolution procedure is demonstrated by the convenience of the scaledup enzymatic experiment carried out on 370 g of substrate in an ordinary flat bottom flask.
Scheme III. a -Formation of acyl-enzyme intermediate via nucleophilic attack of serine oxygen on the acylating agent; bacyl-enzyme intermediate; c -sterically hindered interaction between acyl-enzyme and racemic alcohol.