Premium
Transition‐Metal Catalysis of Triene 6π Electrocyclization: The π‐Complexation Strategy Realized
Author(s) -
Qin Pengjin,
Wang LiAn,
O'Connor Joseph M.,
Baldridge Kim K.,
Li Yifan,
Tufekci Burak,
Chen Jiyue,
Rheingold Arnold L.
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202006992
Subject(s) - conrotatory and disrotatory , catalysis , alkene , stereoselectivity , chemistry , cycloisomerization , stereospecificity , transition metal , ring (chemistry) , combinatorial chemistry , computational chemistry , organic chemistry
Abstract Triene 6π electrocyclization, wherein a conjugated triene undergoes a concerted stereospecific cycloisomerization to a cyclohexadiene, is a reaction of great historical and practical significance. In order to circumvent limitations imposed by the normally harsh reaction conditions, chemists have long sought to develop catalytic variants based upon the activating power of metal–alkene coordination. Herein, we demonstrate the first successful implementation of such a strategy by utilizing [(C 5 H 5 )Ru(NCMe) 3 ]PF 6 as a precatalyst for the disrotatory 6π electrocyclization of highly substituted trienes that are resistant to thermal cyclization. Mechanistic and computational studies implicate hexahapto transition‐metal coordination as responsible for lowering the energetic barrier to ring closure. This work establishes a foundation for the development of new catalysts for stereoselective electrocyclizations.