Synthesis of Optically Pure 1-(2-Pyridinyl)ethylamine and 4-(2-Pyridinyl)-1,3-oxazolin-2-one
摘要:
Several (R)-1-(2-pyridinyl)ethylamines (4) were prepared from (S)-1-(2-pyridinyl)ethanols (L) with complete inversion of the chiral center. Substitution of (S)-1-(2-pyridinyl)ethyl methanesulfonate (2) with sodium azide gave (R)-1-(2pyridinyl)ethyl azide (3) stereospecifically, and reduction of the azide afforded the corresponding amine (4) in good yield. When optically pure 2-silyloxy-1-(2-piridinyl)ethanol was used, 2-silyloxy-1-(2-pyridinyl)ethylamine was obtained, and this was converted to optically pure pyridine-substituted 1,3-oxazolidin-2-one at the 4-position.
描述了由高烯丙基,高炔丙基和烯丙醇衍生的烯炔的分子内Pauson-Khand反应。2-杂芳基取代的均烯丙基,高炔丙基和烯丙醇可以通过高ee(91-99%)的酶解和已知的立体化学方法轻松高效地拆分。从高烯丙基和高炔丙基醇,得到构象最稳定的非对映体环戊二烯并[导出的各对映体富集的烯炔Ç ]吡喃环系统作为唯一的产物,而由烯丙基醇得到非对映体衍生的对映体富集烯炔顺:反式的环戊二烯的混合物[ C ^ ]呋喃铃声系统。
作者:Stefania F. Musolino、O. Stephen Ojo、Nicholas J. Westwood、James E. Taylor、Andrew D. Smith
DOI:10.1002/chem.201604788
日期:2016.12.23
The non‐enzymatic acylative kineticresolution of challenging aryl–alkenyl (sp2 vs. sp2) substituted secondaryalcohols is described, with effective enantiodiscrimination achieved using the isothiourea organocatalyst HyperBTM (1 mol %) and isobutyric anhydride. The kineticresolution of a wide range of aryl–alkenyl substituted alcohols has been evaluated, with either electron‐rich or naphthyl aryl
描述了具有挑战性的芳基-烯基(sp 2与 sp 2 )取代的仲醇的非酶酰化动力学拆分,并使用异硫脲有机催化剂 HyperBTM(1 mol%)和异丁酸酐实现了有效的对映区分。已经评估了各种芳基-烯基取代醇的动力学拆分,其中富电子或萘基芳基取代基与未取代的乙烯基取代基相结合,提供了最高的选择性( S =2-1980)。演示了使用该方案对模型芳基-乙烯基(sp 2与 sp 2 )取代的仲醇进行克级(2.5 g)动力学拆分,可获取每种产物对映体的 >1 g 99:1呃。
Kinetic resolution of allylic alcohols via stereoselective acylation catalyzed by lipase PS-30
作者:Peiran Chen、Peng Xiang
DOI:10.1016/j.tetlet.2011.08.093
日期:2011.11
By using lipase PS-30 as catalyst, the kineticresolution 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.
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 degrees C using Candida antarctica lipase (CAL) to give (R)-acetate and unreacted (S)-alcohol with excellent enantiomeric purities