5912-87-8Relevant articles and documents
One-pot hydroformylation/O-acylation of propenylbenzenes for the synthesis of polyfunctionalized fragrances
Delolo, Fábio G.,Vieira, Gabriel M.,Villarreal, Jesus A.A.,dos Santos, Eduardo N.,Gusevskaya, Elena V.
, p. 272 - 279 (2020/06/17)
A process involving the hydroformylation/O-acylation of propenylbenzenes with a phenolic group is described for eugenol, isoeugenol, chavicol, propenyl guaethol, 2-allylphenol, and 2-allyl-6-methylphenol. The reactions occur in parallel, under the same reaction conditions in anisole, a solvent with an impressive sustainability rank comparable to those of ethanol and water. The products contain formyl and acetoxy moieties, both established olfactory groups in flavor and fragrance industry, and present potential as new fragrance components with less allergenic properties. To the best of our knowledge, this is the first time that a one-pot process involving hydroformylation combined with further functionalization in a remote site is described.
A Pd-Catalyzed Site-Controlled Isomerization of Terminal Olefins
Ren, Wenlong,Sun, Fei,Chu, Jianxiao,Shi, Yian
supporting information, p. 1868 - 1873 (2020/03/03)
An effective Pd-catalyzed isomerization of olefins with 2-PyPPh2 as the ligand is described. A wide variety of trans-2-olefins bearing various functional groups can be obtained with high regio- A nd stereoselectivity under mild reaction conditions. The ligand is crucial for the reaction.
Modular palladium bipyrazoles for the isomerization of allylbenzenes - Mechanistic considerations and insights into catalyst design and activity, role of solvent, and additive effects
Spallek, Markus J.,Stockinger, Skrollan,Goddard, Richard,Trapp, Oliver
experimental part, p. 1466 - 1480 (2012/09/11)
The catalytic activity of novel bidentate N,N-chelated palladium complexes derived from electron excessive, backbone fused 3,3'-bipyrazoles in the selective isomerization of terminal arylpropenoids and 1-alkenes is described. The catalysts are easily modified by appropriate wing tip substitution, while maintaining the same bulky, rigid unreactive aliphatic backbone. Eleven novel palladium complexes with different electronic and steric properties were investigated. Their performance in the palladium(II)-catalyzed isomerization of a series of substituted allylbenzenes was evaluated in terms of electronic as well as steric effects. Besides the clear finding of a general trend towards higher catalyst activity with more electron-donating properties of the coordinated N,N-bidentate ligands, we found that the catalytic process strongly depends on the choice of solvents and additives. Extensive solvent screening revealed that reactions run best in a 2:1 toluene-methanol mixture, with the alcohol employed being a crucial factor in terms of electronic and steric factors. A reaction mechanism involving a hydride addition-elimination mechanism starting with a palladium hydride species generated in situ in alcoholic solutions, as corroborated by experiments using deuterium labeled allylbenzene, seems to be most likely. The proposed mechanism is also supported by the observed reaction rate orders of κobs[cat.]≈1 (0.94), κobs [substrate]=0.20→1.0 (t→∞) and κobs [methanol]=-0.51 for the isomerization of allylbenzene. Furthermore, the influence of acid and base, as well as the role of the halide coordinated to the catalyst, are discussed. The system catalyzes the isomerization of allylbenzenes very efficiently yielding high E:Z selectivities under very mild conditions (room temperature) and at low catalyst loadings of 1 mol% palladium even in unpurified solvents. The integrity and stability of the catalyst system were confirmed by multiple addition reaction cycles, successive filtration and isolation experiments, and the lack of palladium black formation. Copyright
