This title appears in the Scientific Report : 2001 

Total synthesis of (R)- and (S)-semi-vioxanthin
Drochner, D.
Müller, M.
Biotechnologie 2; IBT-2
European journal of organic chemistry (2001) S. 211 - 215
Weinheim Wiley-VCH Verl. 2001
211 - 215
Journal Article
Verfahrenstechnik zur mikrobiellen Gewinnung von Primärmetaboliten
European Journal of Organic Chemistry
Compounds (R)- and (S)-semi-vioxanthin 2 were synthesized by a tandem Michael reaction of orsellinate 3 and the chiral Michael accepters 4. The key step for the formation of lactone (R)-4 is a regio- and enantioselective, enzyme-catalyzed reduction of tert-butyl 3,5-dioxohexanoate (5) by an alcohol-dehydrogenase from Lactobacillus brevis. Compound (S)-4 was synthesized by the Claisen condensation of tert-butyl acetate and ethyl (S)-3-hydroxy-butanoate (8). Cleavage of the benzyloxymethyl groups in the protected (R)- and (S)semi-vioxanthins was achieved by hydrogenolysis to afford (R)-2 and (S)-2, respectively.