107229-53-8Relevant articles and documents
A new route to protected acyloins and their enzymatic resolution with lipases
Scheid, Guenther,Kuit, Wouter,Ruijter, Eelco,Orru, Romano V. A.,Henke, Erik,Bornscheuer, Uwe,Wessjohann, Ludger A.
, p. 1063 - 1074 (2007/10/03)
A series of 16 different 3-acyloxy methyl ketones, the acyloin acetates and butyrates (±)-5, was synthesised by a straight-forward new method through alkylation of tert-butyl 2-acyloxyacetoacetates 3, followed by chemoselective dealkoxy-carbonylation 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.
Improved synthesis of the northern hemisphere of epothilone A by a sharpless asymmetric dihydroxylation
Quitschalle, Monika,Kalesse, Markus
, p. 7765 - 7768 (2007/10/03)
An improved synthesis of the northern hemisphere of epothilone A is described. This approach utilizes the Sharpless asymmetric dihydroxylation of 5-hexen-2-one (allyl acetone) to generate the precursor for the Wittig reaction and the subsequent ring closing metathesis reaction (RCM). This strategy allows to generate precursor 13 as both enantiomers from ready available starting material in a very efficient manner.
