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Cobalt‐Catalyzed E ‐Selective Cross‐Dimerization of Terminal Alkynes: A Mechanism Involving Cobalt(0/II) Redox Cycles
Author(s) -
Ueda Yohei,
Tsurugi Hayato,
Mashima Kazushi
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.201913835
Subject(s) - cobalt , catalysis , chemistry , steric effects , catalytic cycle , medicinal chemistry , propyne , stereochemistry , redox , terminal (telecommunication) , photochemistry , organic chemistry , telecommunications , computer science
A highly E ‐selective cross‐dimerization of terminal alkynes with either terminal silylacetylenes, tert ‐butylacetylene, or 1‐trimethylsilyloxy‐1,1‐diphenyl‐2‐propyne in the presence of a dichlorocobalt(II) complex bearing a sterically demanding 2,9‐bis(2,4,6‐triisopropylphenyl)‐1,10‐phenanthroline, activated with two equivalents of EtMgBr, gives a variety of ( E )‐1,3‐enynes. A well‐characterized diolefin/cobalt(0) complex, with divinyltetramethyldisiloxane, acted as a catalytically active species without any activation, clearly indicating that a cobalt(0) species is involved in the catalytic cycle.