Research On Baker's Yeast Mediated Asymmetric Bioreduction Of Unsaturated Aldehyde And Ketone

In recent years, the synthesis of chiral compounds has become the new division internationally. Many researchers are applying themselves to develop new processes for chiral compound synthesis with high conversion ratio and high stereo-selectivity, in which, biotransformation is attracted interests because of mild reaction condition and high stereo-selectivity.In this thesis,the baker's yeast(whole cell) mediated asymmetric reduction of 2-ethylhex-2-enal, 4-actyl-[2.2] paracyclophane and other unsaturated aldehyde/ketone were studied.Substrate 2-ethylhex-2-enal was synthesized via self-condensation of n-butyraldehyde. The asymmetric bioreduction of thisα,β-unsaturated aldehyde was studied in detail. Effects of different yeast strains, pH value, substrate concentration, reaction time on yield and e.e. value of product (S)-2-ethylhexan-1-ol were evaluated. A high yield (91%) of (S)-2-ethylhexan-1-ol with excellent enantioselectivity was afforded in water-petroleum ether biphasic system. Meanwhile, interesting high reduction rate of 2-ethylhex-2-en-1-ol and unusual increase of e.e. value during the reaction was observed.Substrates 4-actyl-[2.2] paracyclophane, 4-trifluoroactyl-[2.2] paracyclophane, 4-acetalphenyl-[2.2] paracyclophane were obtained by Friedel-Crafts acylation of [2.2] paracyclophane. The baker's yeast mediated asymmetric bioreduction of these unsaturated ketones were studied.Furthermore, the biooxidation of [2.2] paracyclophane and its acylations have also been tried by using Pseudomonas putida (Trevisan) Migula AB92019 and other strains as biocatalyst.