A highly efficient CâC bond formation has been developed through the cross-coupling of primary and secondary alcohols. The corresponding functionalized ketones were obtained with an iridiumâCNP complex as a catalyst through the borrowing hydrogen strategy. The present methodology provides an easy alternative method to aldol reaction derivatives. More importantly, the complexes were also effective catalysts for the alkylation of an aromatic amine with a tertiary alkyl amine.
By employing an easily available [Ru(p-cymene)Cl-2](2)/Xantphos/t-BuOK catalyst system, the alpha-alkylation of ketones was demonstrated by using pyridyl methanol as the alkylating reagents. The synthetic protocol allows synthesizing a wide range of alpha-pyridyl methylated ketones in reasonable to excellent isolated yields with high atom-efficiency. The transformation is operationally simple, the substrate scope is wide, and the starting materials are readily-available. There is no need for addition of alkenes as the hydrogen receptors or the use of stoichiometric amount of base. (C) 2013 Elsevier Ltd. All rights reserved.
Direct α-alkylation of ketones with primary alcohols catalyzed by iridium–CNP complex
The α-alkylation of ketones with primary alcohols was realized by CC cross-coupling with iridium–CNP complexes as catalyst. This reaction proceeds via dehydrogenation reactions, aldol condensation, and hydrogenation using the borrowed hydrogen atoms from alcohols. The pyridyl methanols and other heterocyclic substituted methanols, especially alkyl alcohols, were also suitable for this transformation