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Silver(I)‐Catalyzed Addition of Phenols to Alkyne Cobalt Cluster Stabilized Carbocations
Author(s) -
Valderas Carolina,
Casarrubios Luis,
Lledos Agusti,
Ortuño Manuel A.,
de la Torre María C.,
Sierra Miguel A.
Publication year - 2016
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.201600288
Subject(s) - catalysis , cobalt , chemistry , nucleophile , alkyne , carbocation , phenols , nucleophilic addition , phenol , adduct , medicinal chemistry , catalytic cycle , photochemistry , combinatorial chemistry , organic chemistry
A smooth catalytic method to use phenols as the nucleophilic partner in the Nicholas reaction has been developed. The method uses either Ag I or Au I catalysts with AgClO 4 or AgBF 4 as the most efficient catalysts tested. Neither additional additives nor cocatalysts were required and the formation of the corresponding phenol adducts occurred in excellent yields. The process has the single limitation of the inability of less nucleophilic phenols (4‐nitrophenol) to generate the corresponding adducts. Additionally, the reaction is highly diastereoselective. DFT calculations allow a catalytic cycle to be proposed that involves trimetallic intermediates; the rate‐determining step of the reaction is hydroxy‐group elimination in a cobalt–silver trimetallic intermediate.