Chemistry of insect antifeedants from azadirachta indica (part 4): synthesis towards the limonoid azadirachtin; preparation of a functionalised decalin fragment
作者:Steven V. Ley、Antonio Abad Somovilla、Howard B. Broughton、Donald Craig、Alexandra M.Z. Slawin、Peter L. Toogood、David J. Williams
DOI:10.1016/s0040-4020(01)80075-2
日期:1989.1
Synthetic studies are described towards the functionaliseddecalin (2). This represents an advanced intermediate in a proposed total synthesis of the naturally occurring insectantifeedantazadirachtin (1) involving a late coupling reaction to form the C-8 – C-14 bond. The final route to (2) involved an intramolecular Diels-Alder reaction of (13) and subsequent internal Michael addition to construct
Biocatalytic access to nonracemic γ-oxo esters via stereoselective reduction using ene-reductases
作者:Nikolaus G. Turrini、Răzvan C. Cioc、Daan J. H. van der Niet、Eelco Ruijter、Romano V. A. Orru、Mélanie Hall、Kurt Faber
DOI:10.1039/c6gc02493a
日期:——
The asymmetric bioreduction of [small alpha],[small beta]-unsaturated [gamma]-keto esters usingene-reductasesfrom the OldYellowEnzymefamily proceeds with excellent stereoselectivity and high conversion levels, covering a broad range of acyclic and...
SOLVENT EFFECTS IN REACTIONS OF DIKETONES WITH WITTIG AND WITTIG-HORNER REAGENTS
作者:Sheila Mawaziny、Amal M. Lawny
DOI:10.1080/10426500008046614
日期:2000.8.1
Abstract In a series of reactions between Wittig or Wittig-Horner (Wadsworth-Emmons) reagents and diketones it was found that out of the five solvents tested, for the Wittig reagents, namely dichloromethane, toluene, ethanol, dimethylformamide, and pyridine, only pyridine had a significant effect on the Z:E ratio of isomeric products, percent Z isomer being increased. In contrast to the Wittig reagents
A one-pot consecutive two-enzyme sequential cascade toward chiral γ-butyrolactones using an enoate reductase as well as alcohol dehydrogenases in combination with a glucose dehydrogenase is reported. In this scalable process, the products were obtained in high yield (up to 90%) and with perfect enantioselectivity (98→99% ee). The starting materials, ethyl 4-oxo-pent-2-enoates, are readily accessible
Continuous-flow synthesis of polysubstituted γ-butyrolactones via enzymatic cascade catalysis
作者:Liliang Chu、Xiaoyan Zhang、Jianing Li、Xuelei Deng、Miao Wu、Ya Cheng、Weiping Zhu、Xuhong Qian、Yunpeng Bai
DOI:10.1016/j.cclet.2023.108896
日期:2024.4
Polysubstituted chiral -butyrolactones are the core structural units of many natural products and high value-added flavors and fragrances used in the food and cosmetic industry. Current enzymatic cascade synthesis of these molecules faces the problems of low enzyme activity and phase separation in batch reaction, resulting in low productivity. Herein, we report a new continuous-flow process to synthesize the