Asymmetric syntheses of enantiomeric 3-p-fluorophenyl 1,2,4-trioxane analogues of the antimalarial artemisinin
摘要:
We have devised an asymmetric synthesis of chiral artemisinin analogues (+)-4a and (-)-4a that retain the tricyclic ring system found in the natural product. The key step in the preparation of (+)-4a involves an asymmetric MgCl2 promoted Michael addition of the (R)-(-)pyrrolidinemethanol-derived enamine 8 to acrylonitrile. This gives the corresponding ketone 9 in 50% yield (>95% ee). Subsequent elaboration of 9 provides the trioxane target (+)-4a in greater than 85% ee. Enantiomeric trioxane (-)-4a was prepared in a similar manner using S-(+)-pyrrolidinemethanol in the first step of the sequence. (C) 1999 Elsevier Science Ltd. All rights reserved.
Laboratory Evolution of Robust and Enantioselective Baeyer−Villiger Monooxygenases for Asymmetric Catalysis
作者:Manfred T. Reetz、Sheng Wu
DOI:10.1021/ja906212k
日期:2009.10.28
and induced fit docking suggests potential randomization sites, different from all previous approaches to focused library generation. Sites harboring highly conserved proline in a loop of the WT are targeted. The most active and enantioselective mutants retain the high thermostability of the parent WT PAMO. The success of the "proline" hypothesis in the present system calls for further testing in future
Induced allostery in the directed evolution of an enantioselective Baeyer–Villiger monooxygenase
作者:Sheng Wu、Juan Pablo Acevedo、Manfred T. Reetz
DOI:10.1073/pnas.0911656107
日期:2010.2.16
accepted by the wild type. By using the known X-ray structure of PAMO, a decision was made regarding an appropriate site at which saturation mutagenesis is most likely to generate mutants capable of inducing allostery without any effector compound being present. After screening only 400 transformants, a double mutant was discovered that catalyzes the asymmetric oxidative kinetic resolution of a set of structurally
Enantioselective oxidation by a cyclohexanone monooxygenase from the xenobiotic-degrading Polaromonas sp. strain JS666
作者:Anne K. Alexander、David Biedermann、Michael J. Fink、Marko D. Mihovilovic、Timothy E. Mattes
DOI:10.1016/j.molcatb.2012.03.002
日期:2012.6
-selectivity of the strain JS666 CHMO is similar to that of other CHMO-type enzymes; of note is this enzyme's excellent stereodiscrimination of 2-substituted cyclicketones. The expression system exhibits no activity with ethene or cDCE as substrates under the tested conditions. Phylogenetic analysis shows that sequence variability among cyclohexanone monooxygenases could be a rich source of new enzyme activities
α-substituted cyanocyclohexanones, leading to the corresponding enantiopure caprolactones (ees >97 %). Classical kineticresolution and regiodivergent parallelkineticresolution patterns were observed, depending on the length of the linear chain at the alpha position. Regioselectivity was compared with that of chemical BV oxidations. Cells revealed an outstanding stability since 50 % of the specific
The present invention pertains to a novel process for the preparation of lactones by decomposition of a 1,2,4-trioxepane of formula (I) wherein, R is H or CH
3
, n is 1-14, Rx independently is any substituent on the ring structure, including substituents which form bi- or tricyclic structures, and m is 0-34.
本发明涉及一种通过分解式 (I) 的 1,2,4-三氧杂环庚烷制备内酯的新工艺,其中,R 是 H 或 CH
3
n为1-14,Rx独立地为环结构上的任何取代基,包括形成双环或三环结构的取代基,m为0-34。