N-Heterocyclic Carbene Catalyzed Trifluoromethylation of Carbonyl Compounds
作者:Jinhua J. Song、Zhulin Tan、Jonathan T. Reeves、Fabrice Gallou、Nathan K. Yee、Chris H. Senanayake
DOI:10.1021/ol050568i
日期:2005.5.1
carbene (NHC) catalyzed trifluoromethylation reaction of carbonylcompounds was discovered. Both enolizable and nonenolizable aldehydes and alpha-keto esters undergo facile trifluoromethylation with TMSCF3 at room temperature in the presence of only 0.5-1 mol % of the commercially available NHC (1), providing CF3-substituted alcohols in good yields. Selective trifluoromethylation of aldehydes over ketones
Chemo- and Enantioselective Routes to Chiral Fluorinated Hydroxyketones Using Ketoreductases
作者:Brendan T. Grau、Paul N. Devine、Lisa N. DiMichele、Birgit Kosjek
DOI:10.1021/ol701810v
日期:2007.11.1
ee (>98%) and yield by a chemo- and stereoselective reduction of prochiral methyl/trifluoromethyl diketones using commercially available ketoreductase enzymes. By using p- and m-trifluoroacetyl substituted acetophenones, we demonstrate that ketoreductases can selectively differentiate between methyl and trifluoromethyl ketones within the same molecule. As a result, useful catalysts were identified that
Molecular and Merrifield supported chiral diamines for enantioselective addition of ZnR2 (R = Me, Et) to ketones
作者:Mercedes Calvillo-Barahona、Carlos Cordovilla、Miroslav N. Genov、Jesús M. Martínez-Ilarduya、Pablo Espinet
DOI:10.1039/c3dt51097b
日期:——
reported as active catalysts in the enantioselective addition reactions of ZnR2 to either methyl- or trifluoromethyl-ketones. Subtle changes in the molecular structure of different catalysts are described herein and lead to a dramatic effect in their catalyticactivity. From these findings, we demonstrate the selective reactivity of the ligands used in the addition of ZnR2 (R = Me, Et) to methyl- and tri
phthalimido trifluoroethanol with aryl bromides to furnish α-aryl-α-trifluoromethyl alcohols is reported. This reaction proceeds via a photoinduced charge transfer of an electrondonor–acceptorcomplex between Hantzsch ester and phthalimido trifluoroethanol, followed by 1,2-hydrogen atom transfer, to generate the α-hydroxytrifluoroethyl radical for the cross-coupling of aryl bromides. No exogenous photocatalysts
A nickelcatalyzed synthesis of α-aryl-α-trifluoromethyl alcohols B is presented that exploits the condensation of iodoarenes and the redox active ether A via cross-electrophile coupling. A mechanistic study was conducted using a comprehensive computational investigation that was also supported by ad hoc control experiments and showed that the key 1,2-HAT (Hydrogen Atom Transfer) event results in the
提出了一种镍催化合成 α-芳基-α-三氟甲醇B的方法,该方法利用碘芳烃和氧化还原活性醚A通过交叉亲电子偶联进行缩合。使用综合计算研究进行了机械研究,该研究也得到了特别控制实验的支持,结果表明关键的 1,2-HAT(氢原子转移)事件导致形成以 C 为中心的自由基C' ,该自由基模仿了三氟乙醛的反应活性。