The reaction of dichlorocarbene with β-ethanolamines stereospecific synthesis of epoxides
作者:Luís Castedo、José L. Castro、Ricardo Riguera
DOI:10.1016/s0040-4039(01)91561-8
日期:——
Optically pure β-ethanolamines were converted into epoxides in good yield and with high e.e. ( ⩾, 95%) by reaction with dichlorocarbene. By this method α-aminoacids were successfully converted into synthetically useful epoxides.
Towards a Greener Epoxidation Method: Use of Water-Surfactant Media and Catalyst Recycling in the Platinum-Catalyzed Asymmetric Epoxidation of Terminal Alkenes with Hydrogen Peroxide
Remarkable improvements in enantioselectivity as well as recycle were observed in the catalytic asymmetric epoxidation of terminal alkenes with a chiral, electron-poor platinum(II) catalyst with hydrogen peroxide as terminal oxidant in water-surfactant media.
The divergent synthesis of penaresidin B and its straight side chain analogue was accomplished by constructing an azetidine ring via SN2 type cyclization of protected 2,3-syn-3,4-syn-4-amino-1,3-dihydroxyhept-6-en-2-yl mesylate and late-stage introduction of an alkyl side chain via olefin cross-metathesis of 4-allylazetidine with readily available terminal alkenes. This synthetic route would be useful
Penaresidin B及其直链类似物的发散合成是通过受保护的2,3- syn -3,4- syn -4-氨基-1,3-dihydroxyhept-6的S N 2型环化构建氮杂环丁烷环而完成的-甲-2-烯基磺酸酯和经由4-烯丙基t啶的烯烃与易得的末端烯烃的交叉复分解作用的烷基侧链的后期引入。该合成路线将对合成Penaresidin侧链类似物有用。
Ring-Strain-Enabled Catalytic Asymmetric Umpolung C–O Bond-Forming Reactions of 1,2-Oxazetidines for the Synthesis of Functionalized Chiral Ethers
作者:Binyu Wu、Jinggang Yang、Min Gao、Lin Hu
DOI:10.1021/acs.orglett.0c01916
日期:2020.7.17
An unprecedented catalyticasymmetric umpolung C–O bond-forming reaction of N-nosyl 1,2-oxazetidines with β-keto esters has been achieved in the presence of a chiral phase-transfer catalyst, allowing access to a range of highly functionalized chiral ethers bearing quaternary and no adjacent stereogenic centers with high yields, excellent enantioselectivities, and diastereoselectivities (up to 97% ee