Stereoselectivity of Baker's Yeast Reduction of 2-Propanones: Influence of Substituents.
作者:Viggo Waagen、Vassilia Partali、Ingjerd Hollingsæter、Man Shun Soon Huang、Thorleif Anthonsen、Hari N. Pati、Kirpal S. Bisht、Virinder S. Parmar、George W. Francis
DOI:10.3891/acta.chem.scand.48-0506
日期:——
The stereoselectivity of Baker'syeastreduction of prochiral alpha-oxygenated 2-propanones has been studied by varying the substrate structure. The 1-hydroxy-3-methoxy-3-propanone 1a was reduced to the corresponding alcohol (R)-2a with 88% enantiomeric excess. Replacing the hydroxy group in 1a with phenoxy or benzyloxy (1b and 1c) gave the alcohols (S)-2b and (S)-2c with 53 and 32% ee, respectively
A new dinuclear chiral salen complexes for asymmetric ring opening and closing reactions: Synthesis of valuable chiral intermediates
作者:Santosh Singh Thakur、Shu-Wei Chen、Wenji Li、Chang-Kyo Shin、Seong-Jin Kim、Yoon-Mo Koo、Geon-Joong Kim
DOI:10.1016/j.jorganchem.2005.12.044
日期:2006.4
A new dinuclear chiral Co(salen) complexes bearing group 13 metals have been synthesized and characterized. The easily prepared complexes exhibited very high catalytic reactivity and enantioselectivity for the asymmetric ring opening of epoxides with H2O, chloride ions and carboxylic acids and consequently provide enantiomerically enriched terminalepoxides (>99% ee). It also catalyzes the asymmetric
Dinuclear salen cobalt complex incorporating Y(OTf)<sub>3</sub>: enhanced enantioselectivity in the hydrolytic kinetic resolution of epoxides
作者:Deepak Patel、Ganesh Ram Kurrey、Sandip S. Shinde、Pradeep Kumar、Geon-Joong Kim、Santosh Singh Thakur
DOI:10.1039/c5ra12408e
日期:——
activation of inactive Jacobsen’s chiralsalenCo(II) (salen = N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine) compound is attained by dinuclear chiralsalenCo(III)–OTf complex formation with yttrium triflate. The yttrium metal not only displays a promoting effect on electron transfer, but also assists in forming two stereocentres of a Lewis acid complex with Co(III)–OTf. We found that the binuclear
Hydrolytic Kinetic Resolution of Terminal Epoxides catalyzed by Novel Bimetallic Chiral Co (Salen) Complexes
作者:Rahul B. Kawthekar、Geon‐Joong Kim
DOI:10.1080/00397910701872658
日期:2008.3.28
complexes bearing transition-metal salts have been synthesized. The easily prepared complexes exhibited very high catalytic reactivity and enantioselectivity in hydrolytic kinetic resolution (HKR) of racemicterminalepoxides and consequently provided enantiomericallyenrichedepoxides (up to 99% ee).
已经合成了带有过渡金属盐的新型双金属手性 Co (salen) 配合物。容易制备的配合物在外消旋末端环氧化物的水解动力学拆分 (HKR) 中表现出非常高的催化反应性和对映选择性,因此提供了对映异构体富集的环氧化物(高达 99% ee)。
Synthesis of Optically Pure Terminal Epoxide and 1,2‐Diol via Hydrolytic Kinetic Resolution Catalyzed by New Heterometallic Salen Complexes
作者:Santosh Singh Thakur、Shu‐Wei Chen、Wenji Li、Chang‐Kyo Shin、Yoon‐Mo Koo、Geon‐Joong Kim
DOI:10.1080/00397910600640354
日期:2006.8
The inactive chiral (salen)Cocomplex is easily activated by InCl3 and TlCl3 Lewis acids by forming heterometallic salencomplexes. These complexes show very high catalytic activity for the synthesis of enantiomerically enriched terminal epoxides (>99% ee) and 1,2‐diols simultaneously via hydrolytickineticresolution. Strong synergistic effects of different Lewis acids, Co‐In and Co‐Tl, were exhibited