Catalytic enantioselective synthesis of perfluoroalkyl-substituted β-lactones <i>via</i> a concerted asynchronous [2 + 2] cycloaddition: a synthetic and computational study
作者:Diego-Javier Barrios Antúnez、Mark D. Greenhalgh、Alexander C. Brueckner、Daniel M. Walden、Pilar Elías-Rodríguez、Patrick Roberts、Benjamin G. Young、Thomas H. West、Alexandra M. Z. Slawin、Paul Ha-Yeon Cheong、Andrew D. Smith
DOI:10.1039/c9sc00390h
日期:——
The enantioselective preparation of a range of perfluoroalkyl-substituted β-lactones through an isothiourea (HyperBTM) catalysed reaction using symmetric anhydrides as ammonium enolate precursors and perfluoroalkylketones (RF = CF3, C2F5, C4F9) is reported. Following optimisation, high diastereo- and enantioselectivity was observed for β-lactone formation using C2F5- and C4F9-substituted ketones at
据报道,使用对称酸酐作为烯醇酸铵前体和全氟烷基酮(R F = CF 3,C 2 F 5,C 4 F 9),通过异硫脲(HyperBTM)催化反应对映选择性地制备了一系列全氟烷基取代的β-内酯。优化后,在室温下使用C 2 F 5和C 4 F 9取代的酮可观察到高非对映选择性和对映选择性(26个实例,最高> 95:5 dr和> 99:1 er) ,而对于CF 3而言,最佳的dr和er需要−78°C取代的酮(11个实例,最大> 95:5 dr和> 99:1 er)。通过开环衍生化β-内酯,以及两步转化生成全氟烷基取代的氧杂环丁烷,已证明在不损失立体化学完整性的情况下。密度泛函理论计算与13 C自然丰度KIE研究一起,已被用于通过一致的异步[2 + 2]-环加成途径来探索反应机理,该途径优于逐步的羟醛-内酯化过程。
MAKAROV A. M.; SHADRINA L. P.; NEDUGOV A. N.; DORMIDONTOV YU. P., XIMIYA EHLEMENTOORGANICHESKIX SOEDINENIJ 11, 1U, U, U1 GRUPP PERIODICH. S+
作者:MAKAROV A. M.、 SHADRINA L. P.、 NEDUGOV A. N.、 DORMIDONTOV YU. P.
DOI:——
日期:——
US4835318A
申请人:——
公开号:US4835318A
公开(公告)日:1989-05-30
Fluoride ion catalyzed isomerization of 2-aryl-F-butenes [1]
作者:Donald J. Burton、James A. Headley
DOI:10.1016/s0022-1139(00)82653-6
日期:1981.10
A kinetic study of the fluorideioncatalyzed isomerization of a series of 2-arylF1-butenes shows the reactions to be pseudo first order in olefin at constant fluorideion concentration. The resultant Hammett plot is non-linear witb a concave downward break near σ=0. A two step mechanism involving formation of a carbanionic intermediate is proposed. A change in the rate limiting step causes the break
A Desilylative Approach to Alkyl Substituted C(1)‐Ammonium Enolates: Application in Enantioselective [2+2] Cycloadditions
作者:Yihong Wang、Claire M. Young、Honglei Liu、Will C. Hartley、Max Wienhold、David. B. Cordes、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1002/anie.202208800
日期:2022.9.19
The catalytic generation of unsubstituted and alkylsubstituted C(1)-ammonium enolates from α-silyl-α-alkyl substituted carboxylic acids using the isothiourea HyperBTM has been developed and applied in enantioselective [2+2]-cycloaddition reactions.