191347-92-9Relevant articles and documents
Highly selective bisphosphine ligands for asymmetric hydroformylation of heterocyclic olefins
Zheng, Xin,Xu, Kun,Zhang, Xumu
, p. 1149 - 1152 (2015/02/19)
The bisphosphine ligand 1c is highly efficient and selective for the asymmetric hydroformylation (AHF) of dihydrofuran and pyrrolines. The AHF of 2,3-dihydrofuran yielded the 2-carbaldehyde in up to 93% ee. The remarkable highest regioselectivity of 2,5-dihydrofuran was obtained to date up to 499 β-isomer/α-isomer with ligand 1c. Furthermore, the highest 96% and 92% ee values were accomplished using the same catalytic system in the AHF of N-Boc pyrroline 11 and 14.
Enantiopure narrow bite-angle P-OP ligands: Synthesis and catalytic performance in asymmetric hydroformylations and hydrogenations
Fernández-Pérez, Héctor,Benet-Buchholz, Jordi,Vidal-Ferran, Anton
, p. 15375 - 15384 (2016/02/18)
Herein is reported the preparation of a set of narrow bite-angle P-OP ligands the backbone of which contains a stereogenic carbon atom. The synthesis was based on a Corey-Bakshi-Shibata (CBS)-catalyzed asymmetric reduction of phosphomides. The structure of the resulting 1,1-P-OP ligands, which was selectively tuned through adequate combination of the configuration of the stereogenic carbon atom, its substituent, and the phosphite fragment, proved crucial for providing a rigid environment around the metal center, as evidenced by X-ray crystallography. These new ligands enabled very good catalytic properties in the Rh-mediated enantioselective hydrogenation and hydroformylation of challenging and model substrates (up to 99 % ee). Whereas for asymmetric hydrogenation the optimal P-OP ligand depended on the substrate, for hydroformylation, a single ligand was the highest-performing one for almost all studied substrates: it contains an R-configured stereogenic carbon atom between the two phosphorus ligating groups, and an S-configured 3,3′-diphenyl-substituted biaryl unit. Ligand design: Narrow-bite-angle P-OP ligands incorporating a stereogenic carbon atom in their backbone have been synthesized by Corey-Bakshi-Shibata (CBS)-catalyzed asymmetric reduction of the corresponding intermediates followed by O-phosphorylation. Rhodium complexes of these ligands provided very good catalytic performance in hydroformylations and hydrogenations (see scheme).
Immobilized bisdiazaphospholane catalysts for asymmetric hydroformylation
Adint, Tyler T.,Landis, Clark R.
, p. 7943 - 7953 (2014/06/23)
Condensation reactions of enantiopure bis-3,4-diazaphospholanes (BDPs) that are functionalized with carboxylic acids enable covalent attachment to bead and silica supports. Exposure of tethered BDPs to the hydroformylation catalyst precursor, Rh(acac)(CO)2, yields catalysts for immobilized asymmetric hydroformylation (iAHF) of prochiral alkenes. Compared with homogeneous catalysts, catalysts immobilized on Tentagel resins exhibit similarly high regioselectivity and enantioselectivity. When corrected for apparent catalyst loading, the activity of the immobilized catalysts approaches that of the homogeneous analogues. Excellent recyclability with trace levels of rhodium leaching are observed in batch and flow reactor conditions. Silica-bound catalysts exhibit poorer enantioselectivities.
