Silver(I)‐Catalyzed Addition of Phenols to Alkyne Cobalt Cluster Stabilized Carbocations. Issue 26 (17th May 2016)

• Record Type: Journal Article
• Authors: Valderas, Carolina; Casarrubios, Luis; Lledos, Agusti; Ortuño, Manuel A.; de la Torre, María C.; Sierra, Miguel A.
• Is Part Of: Chemistry. Volume 22:Issue 26(2016)
• Page Start: 9015
• Page End: 9023
• Publication Date: 2016-05-17
• Subjects: density functional calculations -- homogeneous catalysis -- Nicholas reaction -- reaction mechanisms -- silver; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201600288
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: 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 AgClO4 or AgBF4 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. Abstract : Making the unreactive react : Phenols can be used as nucleophilic partners in the Nicholas reaction by using either silver(I) or gold(I) catalysts (see figure). Neither additional additives nor cocatalysts are required and the formation of the corresponding phenol adducts occurs in excellent yields. In contrast, the "classical" Nicholas reaction with phenols is not possible.