Cu-Catalyzed oxidative 1 : 2 couplings of arynes with nucleophilic terminalalkynesunderaerobicconditions are described herein. A mechanistic investigation revealed a plausible involvement of an aryl-Cu(III)-generating pathway. By this method, ubiquitous arenediynes can be efficiently assembled in a single step under mild conditions.
On the Gold-Catalyzed Generation of Vinyl Cations from 1,5-Diynes
作者:Thomas Wurm、Janina Bucher、Sarah B. Duckworth、Matthias Rudolph、Frank Rominger、A. Stephen K. Hashmi
DOI:10.1002/anie.201700057
日期:2017.3.13
Conjugated 1,5‐diynes bearing two aromatic units at the alkyne termini were converted in the presence of a gold catalyst. Under mild conditions, aryl‐substituted dibenzopentalenes were generated. Calculations predict that aurated vinyl cations are key intermediates of the reaction. A bidirectional approach provided selective access to the angular annulated product in high yield, which was explained
The structure and racemization of 1,2-bis(pentaphenylphenyl)benzene
作者:Ha Thuy Thanh Nguyen、Joel T. Mague、Qi Zhao、Christina M. Kraml、Neal Byrne、Robert A. Pascal
DOI:10.1016/j.tet.2019.03.055
日期:2019.5
C2-symmetric conformation in the crystal. Monomethoxy and dimethoxy derivatives of compound 2 were also prepared, and dynamic NMR studies of these compounds yielded a free energy of activation for racemization (ΔG‡rac) of 20.3 kcal/mol at 423 K. The results are compared with estimates of ΔG‡rac for 2 by various DFT methods.
Borylative cyclisation of diynes using BCl<sub>3</sub> and borocations
作者:Andrew J. Warner、Kieron M. Enright、John M. Cole、Kang Yuan、John S. McGough、Michael J. Ingleson
DOI:10.1039/c9ob00991d
日期:——
The borylative cyclisation of 1,2-dialkynyl benzenes with BCl3 leads to dibenzopentalenes (via intramolecular SEAr) or benzofulvenes (via chloride addition) depending on substituents, with stabilised vinyl cation intermediates (e.g. with a p-MeO-C6H4-group) favouring the latter. The use of borocations leads to more selective dibenzopentalene formation, while other diyne frameworks undergo intramolecular
1,2-二炔基苯与BCl 3的硼化环化反应会生成二苯并戊烯(通过分子内S E Ar)或苯并富勒烯(通过氯化物加成),具体取决于取代基,并带有稳定的乙烯基阳离子中间体(例如,对-MeO-C 6 H 4-组)赞成后者。使用borocations引线以更有选择性dibenzopentalene形成,而其他二炔框架经历分子内小号Ë用Ar选择性甚至p -MeO基团。