Biocatalytic Asymmetric Synthesis of Danshensu Borneol Ester by Baker's Yeast

β-(3,4-dihydroxyphenyl) pyruvic acid was first synthesized by Knoevenagel condensation and hydrolysis reactions of 3,4-dihydroxybenzaldehyde. Then, β-(3,4-dihydroxyphenyl) pyruvate borneol ester was prepared from β-(3,4-dihydroxyphenyl) pyruvic acid with borneol in the presence of a catalytic amount of p-toluenesulfonic acid. Finally, biocatalytic synthesis of target product Danshensu borneol ester (DBZ) catalyzed by bread's yeast was obtained. The factors affecting synthesis of DBZ such as amount of glucose, reaction time, pH valve and amount of β-cyclodextrin were systematacially investigated. The results showed that when the amount of β-(3,4-dihydroxyphenyl) pyruvate borneol ester was 0.5 g, the optium reaction conditions were as follows: amount of glucose 30 g, reaction time 24 h, pH 7, amount of β-cyclodextrin 1.5 g. Under these conditons, enantiomeric excess (e.e.) valve of the target product was as high as 84.9%, and S enantiomer was the predominant component. The process in this paper is mild and low cost, and is a very valuable process for the production of DBZ. © 2018, Editorial Office of FINE CHEMICALS. All right reserved.