A facile IrIII-catalyzed benzylicalkylation of arenes with alcohols has been accomplished via borrowing hydrogen (BH) pathways, and the newly developed spirocyclic NHC IrIII pincer complex (Cat A) serves as an efficient catalyst for this atom-economical and greener transformation. Some drug or bioactive molecules and functional material templates can be easily constructed by this strategy.
通过借氢 (BH) 途径实现了一种简单的 Ir III催化的芳烃与醇的苄基烷基化,新开发的螺环 NHC Ir III钳形配合物 (Cat A) 可作为这种原子经济和绿色转化的有效催化剂. 一些药物或生物活性分子和功能材料模板可以通过这种策略轻松构建。
Synthesis of Biindene Derivatives via Pd-Catalyzed Alkene Difunctionalization Reactions
作者:Alma R. Perez、Garret T. Hanks、Evan C. Bornowski、John P. Wolfe
DOI:10.1021/acs.orglett.4c01400
日期:2024.5.24
The palladium-catalyzed cross-coupling of 2-allylphenyl triflate and related electrophiles with substituted indenes affords biindene derivatives in moderate to good yields with high selectivity for thermodynamically preferred alkene isomers. The transformations involve alkene nucleopalladation with indenyl anions, and we also demonstrate that 2-allylphenyl triflates can be transformed to indenes under
Ethylene-bridged C1-symmetric ansa-(3-R-indenyl)(fluorenyl) zirconocene complexes for propylene dimerization or polymerization: The effect of R group
作者:Yan Wang、Wenzhong Huang、Haiyan Ma、Jiling Huang
DOI:10.1016/j.poly.2014.03.019
日期:2014.7
A series of ethylene-bridged C-1-symmetric ansa-(3-R-indenyl)(fluorenyl) zirconocene complexes 3a-i (R = 2[2-(4-methylphenyl)propyl], 3a; R = 2-[2-(3,5-dimethylphenyl)propyl], 3h; R = 2-(2-benzylpropyl), 3c; R = 2-methylbenzyl, 3d; R = 2-(2-cyclohexylpropyl), 3e; R = 2-[2-(1-cyclohexenyl)propyl], 3f; R = 2-(2-n-butylpropyl), 3g; R = cyclohexyl, 3h; R = Pr-i, 3i) were synthesized by a salt metathesis method and characterized by NMR spectroscopy, elemental analysis (or HRMS) and X-ray diffraction (3e and 3h). Upon activation with methylaluminoxane, most of these zirconocene complexes exhibited sufficient catalytic activities up to 2.5 x 10(5) g C-6/(mol-Zr.h) and high selectivities up to 99% toward propylene dimerization, affording 2-methyl-1-pentene as the major isomer which was confirmed by gas chromatography. Remarkably, the selectivity and activity of complexes 3a-i were significantly influenced by the structural features of the substituent on the 3-position of indenyl ring: a pendant aryl or alkyl group linked by a quaternary carbon bridge provided the complex with high selectivities in the range of 89.9-99.0% for 2-methyl-1-pentene and low to moderate catalytic activities; the lack of a quaternary carbon bridge within the substituent would lead to mainly polypropylenes of low molecular weight. The steric hindrance around the active metal center induced by the pendant group might be responsible for the catalytic dimerization behavior, and the presumed mechanism was discussed. In addition, for complexes 3h and 3i, the selectivity for propylene dimerization could also be enhanced with the increase of reaction temperature. Noticeably, most of these ansa-zirconocene complexes exhibit excellent thermal stability at 100 degrees C, which is important with regard to industrial application. (C) 2014 Elsevier Ltd. All rights reserved.
Phase transfer catalyzed tert-alkylations of cyclopentadiene and indene: indications for set processes
作者:Eckehard V. Dehmlow、Christof Bollmann
DOI:10.1016/s0040-4039(00)93552-4
日期:1991.10
Scope and mechanism of the PTC tert-alkylation of cyclopentadienide anion have been investigated. On the side of the anion, the reaction is limited to cyclopentadiene and indene, whereas many tertiary as well as secondary and primary alkylating agents can be employed. Hexamethylcyclopentadiene 8, for instance, is available easily. Tert-alkylations of this type are more effective if 4,4'-bipyridinium salts are present in addition to a phase transfer catalyst. The reactions involve probably an initial single electron transfer (SET) step.