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A New Route to Protected Acyloins and Their Enzymatic Resolution with Lipases
Author(s) -
Scheid Günther,
Kuit Wouter,
Ruijter Eelco,
Orru Romano V. A.,
Henke Erik,
Bornscheuer Uwe,
Wessjohann Ludger A.
Publication year - 2004
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200300338
Subject(s) - chemistry , kinetic resolution , enantiomer , hydrolysis , lipase , alkylation , organic chemistry , catalysis , enzyme , enantiomeric excess , triacylglycerol lipase , enzymatic hydrolysis , biocatalysis , resolution (logic) , enantioselective synthesis , reaction mechanism , artificial intelligence , computer science
A series of 16 different 3‐acyloxy methyl ketones, the acyloin acetates and butyrates (±)‐ 5 , was synthesised by a straightforward new method through alkylation of tert ‐butyl 2‐acyloxyacetoacetates 3 , followed by chemoselective dealkoxycarbonylation of the tert ‐butyloxycarbonyl group in the presence of other ester groups. Subsequent hydrolysis of (±)‐ 5 can be achieved with base to give racemic acyloins 6 , or with lipase catalysis to afford the corresponding non‐racemic acyloins ( S )‐ 6 . The remaining ( R )‐acyloin esters 5 can be racemised and resubjected to the procedure, or hydrolysed chemically. The kinetic resolution with two of the six tested enzymes, CAL‐B and BCL (PS) lipase, proceeded selectively [enantiomeric ratio ( E ) values between 50 and > 200] and most of the acyloins ( S )‐ 6 were obtained in very high enantiomeric excesses (up to > 99% ee ). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)