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Advances in the Pauson–Khand Reaction: Development of Reactive Cobalt Complexes
Author(s) -
Sugihara Takumichi,
Yamaguchi Masahiko,
Nishizawa Mugio
Publication year - 2001
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 - 10.1002/1521-3765(20010417)7:8<1589::aid-chem15890>3.0.co;2-1
Subject(s) - pauson–khand reaction , cobalt , chemistry , catalysis , lewis acids and bases , alkyne , reactivity (psychology) , carbonylation , dimethoxyethane , stoichiometry , photochemistry , combinatorial chemistry , organic chemistry , carbon monoxide , electrode , electrolyte , medicine , alternative medicine , pathology
Three conceptually new methods employing reactive cobalt carbonyl complexes have been developed for the Pauson–Khand reaction. The first method involves activation of alkyne‐dicobalt hexacarbonyls with “hard” Lewis bases. Primary amines dramatically promote the stoichiometric Pauson–Khand reaction. The active cobalt complexes produced in the system exhibit high reducing ability. The second method involves activation of dicobalt octacarbonyl with less electron‐donating “hard” Lewis bases such as 1,2‐dimethoxyethane and water. These Lewis bases were successfully utilized as a promoter for the catalytic Pauson–Khand reaction. The third method employs methylidynetricobalt nonacarbonyl cluster, which exhibits high reactivity in the catalytic Pauson–Khand reaction in the absence of activator. This may be due to facile coordination of the substrate to the metal center through dissociative and associative mechanisms and/or cleavage of one of the cobalt–cobalt bonds.