Enantioselective NHC‐Catalyzed Redox [2+2] Cycloadditions with Perfluoroketones: A Route to Fluorinated Oxetanes
作者:Alyn T. Davies、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1002/chem.201504256
日期:2015.12.21
carbene (NHC) catalyzedredox formal [2+2] cycloaddition between α‐aroyloxyaldehydes and perfluoroketones, followed by ring‐opening in situ delivers a variety of perfluorinated β‐hydroxycarbonyl compounds in good yield, and excellent diastereo‐ and enantioselectivity. Through a reductive work‐up and subsequent cyclization, this protocol offers access to highly substituted fluorinatedoxetanes in two
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。
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.
Rhodium and Isothiourea Dual Catalysis: Enantiodivergent Transformation of Terminal Alkynes
作者:Tao Fan、Zhipeng Shi、Qian-Wei Gong、Jin Song、Liu-Zhu Gong
DOI:10.1021/acs.orglett.4c00029
日期:2024.2.23
A dual rhodium/isothiourea catalytic system was developed for the enantiodivergent transformation of terminal alkynes. Under synergistic rhodium/isothiourea dual catalysis, terminal alkynes can be creatively utilized as precursors for C1-ammonium enolate species, which subsequently participate in [4 + 2] and [2 + 2] annulation reactions with α,β-unsaturated ketimines or ketones, respectively. A wide
New Fluorous Photoaffinity Labels (F-PAL) and Their Application in V-ATPase Inhibition Studies
作者:Nadja Burkard、Tobias Bender、Johannes Westmeier、Christin Nardmann、Markus Huss、Helmut Wieczorek、Stephanie Grond、Paultheo von Zezschwitz
DOI:10.1002/ejoc.200901463
日期:2010.4
product pool from Streptomyces producer strains. The labelled derivatives 17 and 18 were efficiently purified by fluorous solid-phase extraction. Functional biochemical assays with the V-ATPase holoenzymes proofed strong inhibition activities. So far, radioactive isotopes or biotin-tags have mainly been used for tracing compounds in photoaffinitystudies. The C 4 F 9 - and C 8 F 17 -fluorous tags aim to
(三氟甲基)二氮丙啶是成熟的光亲和标签 (PAL),用于生化研究以创建共价配体 - 受体键。两种新的具有全氟丁基和全氟辛基链 (F-PAL) 的二氮杂苯甲酸 8b,c 由对溴苯甲醛有效制备,并连接到高效特异的 V-ATPase 抑制剂 21-deoxyconcanolide A (2) 和巴弗洛霉素 A 1 (5) ,来自链霉菌生产菌株的天然产物池。标记的衍生物 17 和 18 通过氟固相萃取有效纯化。使用 V-ATPase 全酶进行的功能性生化分析证明了其具有很强的抑制活性。到目前为止,放射性同位素或生物素标签主要用于追踪光亲和研究中的化合物。C 4 F 9 - 和C 8 F 17 - 含氟标签旨在通过含氟色谱和MS 分析实现对标记肽片段的有利分离和鉴定。因此,F-PAL 代表了一种用于结合位点测定的创新概念,应该会显着加速和简化此类生化研究。