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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(46):14810-14813
Exploratory research into the critical steps in metal–organic framework (MOF) activation involving solvent exchange and solvent evacuation are reported. It is discovered that solvent exchange kinetics are extremely fast, and minutes rather days are appropriate for solvent exchange in many MOFs. It is also demonstrated that choice of a very low surface tension solvent is critical in successfully activating challenging MOFs. MOFs that have failed to be activated previously can achieve predicted surface areas provided that lower surface tension solvents, such as n‐hexane and perfluoropentane, are applied. The insights herein aid in the efficient activation of MOFs in both laboratory and industrial settings and provide best practices for avoiding structural collapse. 相似文献
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Tao Xu Guangbin Dong 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(40):10909-10912
The first total syntheses of the proposed structure of cycloinumakiol ( 1 ) and its C5 epimer ( 18 ) are achieved in a concise and efficient fashion. Starting from the known 3‐hydroxybenzocyclobutenone, 1 and 18 are obtained in nine and five steps with overall yields of 15 % and 33 %, respectively. The key for the success of this approach is the use of a catalytic C C activation strategy for constructing the tetracyclic core of 1 through carboacylation of a sterically hindered trisubstituted olefin with benzocyclobutenone. In addition, the structure of the natural cycloinumakiol was reassigned to 19‐hydroxytotarol ( 7 ) through X‐ray diffraction analysis. This work demonstrates the potential of C C activation for streamlining complex natural product synthesis. 相似文献
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Xiaolei Huang Yan Wang Jingbo Lan Jingsong You 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(32):9536-9540
Disclosed herein is a RhIII‐catalyzed chelation‐assisted activation of unreactive C H bonds, thus enabling an intermolecular amidation to provide a practical and step‐economic route to 2‐(pyridin‐2‐yl)ethanamine derivatives. Substrates with other N‐donor groups are also compatible with the amidation. This protocol proceeds at room temperature, has a relatively broad functional‐group tolerance and high selectivity, and demonstrates the potential of rhodium(III) in the promotive functionalization of unreactive C H bonds. A rhodacycle having a SbF6− counterion was identified as a plausible intermediate. 相似文献
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Masato Ohashi Mitsutoshi Shibata Sensuke Ogoshi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(49):13796-13800
A chemoselective C(sp2) F or C(sp3) F bond activation of hexafluoropropylene (HFP) was achieved by adopting the proper combination of a Lewis acid co‐additive with a ligand which coordinates Pd0. The treatment of [(η2‐HFP)Pd(PCy3)2] with B(C6F5)3 allowed a chemoselective C(sp3) F bond cleavage of HFP to give a unique cationic perfluoroallypalladium complex. In this complex, the coordination mode of the perfluoroallyl ligand was considered to be of the unique η2‐fashion. 相似文献