33197-63-6Relevant articles and documents
Palladium-catalyzed allylic substitution with (η6-Arene- CH2Z)Cr(CO)3-based nucleophiles
Zhang, Jiadi,Stanciu, Corneliu,Wang, Beibei,Hussain, Mahmud M.,Da, Chao-Shan,Carroll, Patrick J.,Dreher, Spencer D.,Walsh, Patrick J.
, p. 20552 - 20560 (2012/02/13)
Although the palladium-catalyzed Tsuji-Trost allylic substitution reaction has been intensively studied, there is a lack of general methods to employ simple benzylic nucleophiles. Such a method would facilitate access to "α-2-propenyl benzyl" motifs, which are common structural motifs in bioactive compounds and natural products. We report herein the palladium-catalyzed allylation reaction of toluene-derived pronucleophiles activated by tricarbonylchromium. A variety of cyclic and acyclic allylic electrophiles can be employed with in situ generated (η6-C 6H5CHLiR)Cr(CO)3 nucleophiles. Catalyst identification was performed by high throughput experimentation (HTE) and led to the Xantphos/palladium hit, which proved to be a general catalyst for this class of reactions. In addition to η6-toluene complexes, benzyl amine and ether derivatives (η6-C6H5CH 2Z)Cr(CO)3 (Z = NR2, OR) are also viable pronucleophiles, allowing C-C bond-formation α to heteroatoms with excellent yields. Finally, a tandem allylic substitution/demetalation procedure is described that affords the corresponding metal-free allylic substitution products. This method will be a valuable complement to the existing arsenal of nucleophiles with applications in allylic substitution reactions.
Addition de Carbanions α Benchrotreniques sur Divers Aldehydes non Enolisables; Evolution des Produits Primaires d'Addition par Oxidation d'Oppenauer-Woodward, influence de la Substitution
Senechal-Tocquer, M. C.,Senechal, D.,Bihan, J. Y. Le,Gentric, D.,Caro, B.
, p. 353 - 364 (2007/10/02)
Aromatic hydrocarbons complexed with a Cr(CO)3 unit react with benzaldehydes and furfural in THF and in presence of t-BuOK at the benzylic position to give condensation products in good yields.Formation of ketones by in situ Oppenauer-Woodward oxidation is observed.Influence of ring substituents on this formation is discussed.
