Chemoenzymatic Synthesis of Both Enantiomers of 3-Hydroxy-2,2-dimethylcyclohexanone
摘要:
The stereoselective acetylation of meso-2,2-dimethyl-1,3-cyclohexanediol by vinyl acetate in the presence of three lipases gave the (1R,3S)-monoester in high enantiomeric excess (ee >= 98%). The hydrolysis of the corresponding meso-diacetate in the presence of Candida antarctica lipase in phosphate buffer provided the opposite enantiomer. Optically active monciacetates were converted to both enantiomers of 3-hydroxy-2.2-dimethylcyclohexanone, a versatile chiral building block.
Asymmetric reduction of ketones using recombinant E. coli cells that produce a versatile carbonyl reductase with high enantioselectivity and broad substrate specificity
The gene encoding a versatile biocatalyst that shows highenantioselectivity for a variety of ketones, SCR (Saccharomyces cerevisiae carbonyl reductase), has been identified, cloned, and expressed in Escherichia coli. Two types of expression systems with high NADPH-regenerating capacities have been constructed. One is the tandem system, where the genes encoding SCR and GDH (glucose dehydrogenase) are
编码,显示出对多种酮具有高对映选择性的通用基因的基因SCR(酿酒酵母羰基还原酶)已在大肠杆菌中鉴定,克隆和表达。已经构建了具有高NADPH再生能力的两种类型的表达系统。一个是串联系统,其中编码SCR和GDH(葡萄糖脱氢酶)的基因位于同一质粒中,另一个是双质粒系统,其中SCR和GDH的每个基因位于可以共存的单独质粒中在一个大肠杆菌细胞中 重组大肠杆菌不对称还原酮细胞产生合成有用的20种醇,其中11种对映体纯。这些产品之一的生产率高达41 g / L。
A Negishi cross-coupling reaction enables the total synthesis of (+)-stachyflin
present a full account on the development of the totalsynthesis of the antiviral meroterpenoid (+)-stachyflin. The decalin subunit is rapidly accessed by an exo-selective Diels–Alder reaction, whereas the isonindolinone was synthesized via a highly efficient and practical de novo route starting from dimedone. A challenging sp2–sp3 Negishicross-couplingreaction enabled construction of the crucial C15–C16
The indium-catalyzed allylation reaction was performed in good yields and short reaction time with various cyclohexanones in water. Aqueous facial amphiphilic carbohydrates solutions were also screened for their potency to modify the stereochemical outcome of the reaction. (C) 2010 Elsevier Ltd. All rights reserved.