Observations on the intramolecular Heck reactions of aromatic chlorides using palladium/imidazolium salts
作者:Stephen Caddick、William Kofie
DOI:10.1016/s0040-4039(02)02340-7
日期:2002.12
The intramolecular Heck reaction of aromatic amines and ethers using palladium/imidazoliumsalts is described. The use of tetra-n-butylammonium halide salts facilitates the reactivity of aromatic chlorides. An unexpected and novel palladium-mediated cyclisation is also described leading to the formation of a tricyclic adduct.
The electrochemical, Pd-catalyzed cleavage of the CO bond of allyl arylethers has been examined; the method constitutes a new alternative for allyl ether deprotection. The allyl transfer from the allyl ether to the carbonyl group in 2-allyloxy benzaldehydes is reported and is an example of allyl-Pd reactivity umpolung. Pd(II) complexes, associated to several nitrogen ligands are efficient catalyst
The synthesis of the new complexes [Ru(Cp*)(L)(MeCN)2][PF6] (L = Ph2POMe or Ph2P-o-tolyl) and Ru(Cp*)[Ph2PCH2C(tBu)=O](MeCN)}[PF6] (2a–c) is achieved starting from [Ru(Cp*)(MeCN)3][PF6]. The acetonitrile ligands in complexes 2a–c are labile, as emphasised by the easy formation of Ru(Cp*)(CO)2[Ph2PCH2C(=O)tBu]}[PF6] (3). The keto-phosphane is used as a tool to convert 3 into Ru(Cp*)(CO)[Ph2PCH2C(tBu)=O]}[PF6]
Ruthenium-CatalyzedO-Allylation of Phenols from Allylic Chloridesvia Cationic[Cp*(η3-allyl)(MeCN)RuX][PF6] Complexes
作者:Mbaye D. Mbaye、Bernard Demerseman、Jean-Luc Renaud、Loïc Toupet、Christian Bruneau
DOI:10.1002/adsc.200404023
日期:2004.6
from the reaction of [Cp*(MeCN)3Ru][PF6] with allylic halides were identified as intermediate catalytic species. An X-ray structure determination of the complex [Cp*(MeCHCHCH2)(MeCN)RuBr][PF6] disclosed an (endo-trans-MeCHCHCH2) allylic ligand. The structural information obtained from the study of Cp*(allyl)Ru(IV) complexes indicated that electronic effects at the coordinated allylic ligand likely account
chlorides by carbon nucleophiles and phenols, respectively. After generation of diaminocarbene species upon deprotonation by tBuOK, their association with [Cp*Ru(MeCN)3]PF6 induces a very high regioselectivity in favor of the branched isomers when cinnamyl derivatives are used as starting substrates. They also provide good regioselectivities for the allylation of phenols by unsymmetrical aliphatic allylic