204244-73-5Relevant articles and documents
Isothiourea-Catalysed Acylative Kinetic Resolution of Aryl–Alkenyl (sp2vs. sp2) Substituted Secondary Alcohols
Musolino, Stefania F.,Ojo, O. Stephen,Westwood, Nicholas J.,Taylor, James E.,Smith, Andrew D.
supporting information, p. 18916 - 18922 (2016/12/26)
The non-enzymatic acylative kinetic resolution of challenging aryl–alkenyl (sp2vs. sp2) substituted secondary alcohols is described, with effective enantiodiscrimination achieved using the isothiourea organocatalyst HyperBTM (1 mol %) and isobutyric anhydride. The kinetic resolution of a wide range of aryl–alkenyl substituted alcohols has been evaluated, with either electron-rich or naphthyl aryl substituents in combination with an unsubstituted vinyl substituent providing the highest selectivity (S=2–1980). The use of this protocol for the gram-scale (2.5 g) kinetic resolution of a model aryl–vinyl (sp2vs. sp2) substituted secondary alcohol is demonstrated, giving access to >1 g of each of the product enantiomers both in 99:1 e.r.
Kinetic resolution of allylic alcohols via stereoselective acylation catalyzed by lipase PS-30
Chen, Peiran,Xiang, Peng
experimental part, p. 5758 - 5760 (2011/12/03)
By using lipase PS-30 as catalyst, the kinetic resolution of a series of racemic allylic alcohols has been achieved via stereoselective acylation. The value of kinetic enantiomeric ratio (E) reached up to 968. Substituent effect is briefly discussed.
Stereoselective synthesis of optically active cyclopenta[c]pyrans and cyclopenta[c]furans by the intramolecular Pauson-Khand reaction
Sezer, Serdar,Sahin, Ertan,Tanyeli, Cihangir
experimental part, p. 476 - 485 (2010/07/04)
An intramolecular Pauson-Khand reaction of enynes derived from homoallyl, homopropargyl, and allyl alcohols is described. 2-Heteroaryl-substituted homoallyl, homopropargyl, and allyl alcohols are easily and efficiently resolved through enzymatic resolution in high ee (91-99%) and with a known stereochemistry. Each enantiomerically enriched enyne derived from homoallyl and homopropargyl alcohols affords the conformationally most stable diastereomeric cyclopenta[c]pyran ring system as the sole product, whereas enantiomerically enriched enynes derived from allyl alcohols give a diastereomeric cis:trans mixture of the cyclopenta[c]furan ring system.
Chiral Pyridines: Optical Resolution of 1-(2-Pyridyl)- and 1-[6-(2,2′-Bipyridyl)]ethanols by Lipase-Catalyzed Enantioselective Acetylation
Uenishi, Jun'ichi,Hiraoka, Takao,Hata, Shinichiro,Nishiwaki, Kenji,Yonemitsu, Osamu,Nakamura, Kaoru,Tsukube, Hiroshi
, p. 2481 - 2487 (2007/10/03)
The resolution of racemic 1-(2-pyridyl)ethanols 2a-n, including the 2,2′-bipyridyl and isoquinolyl derivatives, by lipase-catalyzed asymmetric acetylation with vinyl acetate is reported. The reactions were carried out in diisopropyl ether at either room temperature or 60°C using Candida antarctica lipase (CAL) to give (R)-acetate and unreacted (S)-alcohol with excellent enantiomeric purities in good yields. The reaction rate was relatively slow at room temperature for substrates bearing an sp3-type carbon at the 6-position on the pyridine ring, such as 2c, 2d, and 2e, and for those bearing 1-hydroxypropyl and allyl groups at the 2-position on the pyridine ring, such as 21 and 2m. In such cases, a higher temperature was required. Thus, when the reaction was conducted at 60°C, it was accelerated 3- to 7-fold without losing the high enantiospecificity. However, the reaction of homoallylic alcohol 2n was not complete, even when the reaction was continued for a longer period of time at 60°C. This enzymatic resolution can be used practically in a wide range of reaction scales from 10 mg to 10 g or more. This catalyst can be used repeatedly with a 5-10% loss of the initial activity with each use.
