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A Combined Experimental and Computational Study on the Cycloisomerization of 2‐Ethynylbiaryls Catalyzed by Dicationic Arene Ruthenium Complexes
Author(s) -
Yamamoto Yoshihiko,
Matsui Kazuma,
Shibuya Masatoshi
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201500248
Subject(s) - cycloisomerization , ruthenium , phenanthrenes , chlorobenzene , catalysis , chemistry , combinatorial chemistry , photochemistry , organic chemistry , phenanthrene
Ruthenium‐catalyzed cycloisomerization of 2‐ethynylbiaryls was investigated to identify an optimal ruthenium catalyst system. A combination of [η 6 ‐( p ‐cymene)RuCl 2 (PR 3 )] and two equivalents of AgPF 6 effectively converted 2‐ethynylbiphenyls into phenanthrenes in chlorobenzene at 120 °C over 20 h. Moreover, 2‐ethynylheterobiaryls were found to be favorable substrates for this ruthenium catalysis, thus achieving the cycloisomerization of previously unused heterocyclic substrates. Moreover, several control experiments and DFT calculations of model complexes were performed to propose a plausible reaction mechanism.