1362860-36-3Relevant academic research and scientific papers
Well-Defined and Robust Rhodium Catalysts for the Hydroacylation of Terminal and Internal Alkenes
Prades, Amparo,Fernández, Maitane,Pike, Sebastian D.,Willis, Michael C.,Weller, Andrew S.
supporting information, p. 8520 - 8524 (2015/11/27)
A Rh-catalyst system based on the asymmetric ligand tBu2PCH2P(o-C6H4OMe)2 is reported that allows for the hydroacylation of challenging internal alkenes with β-substituted aldehydes. Mechanistic studies point to the stabilizing role of both excess alkene and the OMe-group.
Intermolecular hydroacylation: High activity rhodium catalysts containing small-bite-angle diphosphine ligands
Chaplin, Adrian B.,Hooper, Joel F.,Weller, Andrew S.,Willis, Michael C.
supporting information; experimental part, p. 4885 - 4897 (2012/05/04)
Readily prepared and bench-stable rhodium complexes containing methylene bridged diphosphine ligands, viz. [Rh(C6H5F)(R 2PCH2PR'2)][BArF4] (R, R' = tBu or Cy; ArF = C6H3-3,5- (CF3)2), are shown to be practical and very efficient precatalysts for the intermolecular hydroacylation of a wide variety of unactivated alkenes and alkynes with β-S-substituted aldehydes. Intermediate acyl hydride complexes [Rh(tBu2PCH 2PtBu2)H{κ2(S,C)-SMe(C 6H4CO)}(L)]+ (L = acetone, MeCN, [NCCH 2BF3]-) and the decarbonylation product [Rh(tBu2PCH2PtBu2)(CO) (SMePh)]+ have been characterized in solution and by X-ray crystallography from stoichiometric reactions employing 2-(methylthio) benzaldehdye. Analogous complexes with the phosphine 2-(diphenylphosphino) benzaldehyde are also reported. Studies indicate that through judicious choice of solvent and catalyst/substrate concentration, both decarbonylation and productive hydroacylation can be tuned to such an extent that very low catalyst loadings (0.1 mol %) and turnover frequencies of greater than 300 h-1 can be achieved. The mechanism of catalysis has been further probed by KIE and deuterium labeling experiments. Combined with the stoichiometric studies, a mechanism is proposed in which both oxidative addition of the aldehyde to give an acyl hydride and insertion of the hydride into the alkene are reversible, with the latter occurring to give both linear and branched alkyl intermediates, although reductive elimination for the linear isomer is suggested to have a considerably lower barrier.
