Structure-Guided Regulation in the Enantioselectivity of an Epoxide Hydrolase to Produce Enantiomeric Monosubstituted Epoxides and Vicinal Diols via Kinetic Resolution
Structure-guided microtuning of an Aspergillus usamii epoxide hydrolase was executed. One mutant, A214C/A250I, displayed a 12.6-fold enhanced enantiomeric ratio (E = 202) toward rac-styrene oxide, achieving its nearly perfect kinetic resolution at 0.8 M in pure water or 1.6 M in n-hexanol/water. Several other beneficial mutants also displayed significantly improved E values, offering promising biocatalysts
对Aspergillus usamii环氧水解酶进行了结构引导的微调。一种突变体 A214C/A250I对消旋-氧化苯乙烯的对映体比 ( E = 202)提高了 12.6 倍,在纯水中 0.8 M 或正己醇/水中 1.6 M 时实现了近乎完美的动力学分辨率。其他一些有益的突变体也显示出显着提高的E值,为获得 19 种结构多样的手性单取代环氧化物(97.1 – ≥ 99% ee s)和邻二醇(56.2–98.0% ee p)提供了有希望的生物催化剂,并且产率很高。
“Cassette” In Situ Enzymatic Screening Identifies Complementary Chiral Scaffolds for Hydrolytic Kinetic Resolution Across a Range of Epoxides
作者:Sangeeta Dey、Douglas R. Powell、Chunhua Hu、David B. Berkowitz
DOI:10.1002/anie.200701280
日期:2007.9.17
‘Cassette’-ISES (In Situ Enzymatic Screening) Identifies Complementary Chiral Scaffolds for Hydrolytic Kinetic Resolution Across a Range of Epoxides A new ‘Cassette’-In Situ Enzymatic Screen (ISES) for combinatorial catalysis is introduced. This allows the experimentalist to obtain an information-rich readout, in real time, providing an estimate of the sense and magnitude of enantioselectivity across more than one substrate. In its first iteration, the screen identified CoIII-salen catalysts with β-pinene- and α-naphthylalanine-derived chiral scaffolds with broad, yet complementary, substrate specificities.
Enantioselectivities of yeast epoxide hydrolases for 1,2-epoxides
作者:Adriana L. Botes、Carel A.G.M. Weijers、Piet J. Botes、Martie S. van Dyk
DOI:10.1016/s0957-4166(99)00355-9
日期:1999.8
Kinetic resolution of homologous series of unbranched 1,2-epoxyalkanes (C-4 to C-12), 1,2-epoxyalkenes (C-4, C-6 and C-8), a 2,2-dialkylsubstituted epoxide (2-methyl-1,2-epoxyheptane) and a benzyloxy-substituted epoxide (benzyl glycidyl ether) was investigated using resting cells of 10 different yeast strains. Biocatalysts with excellent enantioselectivity (E>100) and high initial reaction rates (>300 nmol/min/mg dry weight) were found for the 2-monosubstituted aliphatic epoxides C-6 to C-8. Yeast strains belonging to the genera Rhodotorula, Rhodosporidium and Trichosporon all preferentially hydrolyzed (R)-1,2-epoxides with retention of configuration. The epoxide hydrolases of all the yeast strains are membrane-associated. (C) 1999 Elsevier Science Ltd. All rights reserved.
Total Synthesis of 34-Hydroxyasimicin and Its Photoactive Derivative for Affinity Labeling of the Mitochondrial Complex I
作者:Hongna Han、Mantosh K. Sinha、Lawrence J. D'Souza、Ehud Keinan、Subhash C. Sinha
DOI:10.1002/chem.200305557
日期:2004.5.3
total synthesis of the 34-hydroxyasimicin and its 3-(4-benzoylphenyl)propionate ester was achieved by means of a convergent synthetic strategy. This ester, which contains eight asymmetric centers, represents the first photoaffinity-labeling agent that is derived from an Annonaceous acetogenin. The key transformations in the synthesis include the Sharpless asymmetric dihydroxylation reaction, the Wittig
An efficient and versatile synthesis of the butenolide subunit of 4-hydroxylated annonaceous acetogenins
作者:Thomas R. Hoye、Paul E. Humpal、Jorge I. Jiménez、Michael J. Mayer、Lushi Tan、Zhixiong Ye
DOI:10.1016/s0040-4039(00)78332-8
日期:1994.10
Title butenolides 2 have been synthesized by an efficient and versatile route that provides access to any stereoisomer by use of individual enantiomers of the precursors 3-butyn-2-ol and terminal epoxides.