Synthesis of tetralin and chromane derivatives via In-catalyzed intramolecular hydroarylation
摘要:
IN(OTf)(3) was found to be an effective catalyst for the cyclization of omega-aryl-1-alkenes to form tetralin and chromane derivatives Compared with the known Ru-catalyzed version, the In-catalyzed intramolecular cyclization was found to give higher yields and cleaner reactions in some cases The use of cheaper indium salts instead of the expensive noble metal Ru can be advantageous when the reaction is run on a large scale (C) 2010 Elsevier Ltd All rights reserved
[EN] HIGHLY DIASTEREOSELECTIVE CONSTRUCTION OF THE 4,5-SPIROCYCLE VIA PALLADIUM-CATALYZED INTRAMOLECULAR ALKENYLATION [FR] CONSTRUCTION FORTEMENT DIASTÉRÉOSÉLECTIVE DU 4,5-SPIROCYCLE PAR ALCÉNYLATION INTRAMOLÉCULAIRE CATALYSÉE PAR PALLADIUM
affect thiiranium-based polyenecyclizations in moderate to good yields. In most of the substrates probed, these reagents provide superior yields to previously reported alternatives. In addition, initial efforts to develop an asymmetric variant of the process through the use of chiral versions of these reagents are discussed. Although electrophile-promoted polyenecyclizations have long been a mainstay
ZnI<sub>2</sub>/Zn(OTf)<sub>2</sub>-TsOH: a versatile combined-acid system for catalytic intramolecular hydrofunctionalization and polyene cyclization
作者:Ting-Hung Chou、Bo-Hung Yu、Rong-Jie Chein
DOI:10.1039/c9cc07242j
日期:——
combined-acid system using a zinc(II) salt [ZnI2 or Zn(OTf)2] and p-toluene sulfonic acid (TsOH) was investigated for catalytic cationic cyclizations, including intramolecular hydrocarboxylation, hydroalkoxylation, hydroamination, hydroamidation, hydroarylation and polyenecyclizations. This reaction provides easy access to five- and six-membered O- and N-containing saturated heterocyclic compounds, tetrahydronaphthalene
Stable Bromiranium Ions with Weakly-Coordinating Counterions as Efficient Electrophilic Brominating Agents
作者:Christoph Ascheberg、Jonathan Bock、Florenz Buß、Christian Mück-Lichtenfeld、Constantin G. Daniliuc、Klaus Bergander、Fabian Dielmann、Ulrich Hennecke
DOI:10.1002/chem.201701643
日期:2017.8.25
Electrophilic halogenating agents are an important class of reagents in chemical synthesis. Herein, we show that sterically demanding bromiranium ions with weakly coordinating counterions are highly reactive electrophilic brominating agents. Despite their high reactivity these reagents are stable, in one case even under ambient conditions and can be applied in electrophilic halogenations of alkenes
Specific and Strong Acceleration of Nitrosation by Nitrosyl Sulfonates Using the Bis-Coordinating Lewis Acid TiCl<sub>4</sub> or SnCl<sub>4</sub>
作者:G. Sudhakar Reddy、E. J. Corey
DOI:10.1021/acs.orglett.3c03768
日期:2024.1.19
Nitrosyl triflate is an excellent donor of NO+ to C═C and very unreactive benzenoids, in contrast to the much less reactive nitrosyl mesylate. However, both of these reagents are strongly activated by the bis-coordinating Lewis acids TiCl4 and SnCl4 and become super reactive NO+ donors. Strong catalysis and activation are even observed with the inherently less electrophilic nitrosyl trifluoroacetate
与活性较低的甲磺酸亚硝酰酯相比,三氟甲磺酸亚硝酰酯是 NO +向 C=C 和非常不活泼的苯类化合物的极佳供体。然而,这两种试剂均被双配位路易斯酸TiCl 4和SnCl 4强烈活化,并成为超反应性NO +供体。甚至用本身亲电性较低的三氟乙酸亚硝酰酯也观察到强催化和活化作用。单配位强路易斯酸,例如MeAlCl 2 ,相对无效。
[EN] HIGHLY DIASTEREOSELECTIVE CONSTRUCTION OF THE 4,5-SPIROCYCLE VIA PALLADIUM-CATALYZED INTRAMOLECULAR ALKENYLATION<br/>[FR] CONSTRUCTION FORTEMENT DIASTÉRÉOSÉLECTIVE DU 4,5-SPIROCYCLE PAR ALCÉNYLATION INTRAMOLÉCULAIRE CATALYSÉE PAR PALLADIUM
申请人:UNIV CHICAGO
公开号:WO2018213442A1
公开(公告)日:2018-11-22
A diastereoselective method of preparing benzofuran-based 4,5-spirocycles via metal catalyzed alkenylation is described. The method can be used to provide compounds containing the benzofuranone-4,5-spirocyclic motif of the phainanoids, a class a natural products having immunosuppressive activity. Synthetic analogs of phainanoids, e.g., compounds that mimic the structure of the "western" part of the structure of the phainanoids and that contain the benzofuranone-4,5-spirocycle are described, as well as their synthetic intermediates, and their methods of synthesis.