Neomenthyldiphenylphosphine catalyst

With [Rh2Cl2(CO)4] as catalyst precursor, together with (R)-benzyl(methyl)phenylphosphine or neomenthyldiphenylphosphine, styrene was hydroformylated to 2- and 3-phenylpropanal (equation 65) 2-phenylpropanal was the major product. The optical yields were not given, but... 

FIG. 8. Asymmetric homogeneous hydrogenation with a neomenthyldiphenylphosphine (NMDPP) catalyst. 

Hydrosilylation of monosubstituted alkenes with palladium catalysts and trichlorosilane follows a course which favors branched products. By using a chiral phosphine ligand, asymmetric reaction is feasible. Initially, menthyldiphenylphosphine (MDPP, 93) and neomenthyldiphenylphosphine (NMDPP, 94) were employed with little success. Later, (/ )-/VA -dimethyl-l-[(S)-2-diphenylphosphinoferroce-nyl]ethylamine [(R)-(S)-PPFA] (95) and its enantiomer were prepared, and these have proved to be the... 

HYDROGENATION, ASYMMETRIC (-)-and (+)-2,3-0-IsopropyIidene-2,3-dihydroxy-l,4-bis(diphenyIphosphine)butane. Neomenthyldiphenylphosphine. HYDROGENATION CATALYSTS frthap/o-AlIyltris(trimethylphosphite)cobalt(I). Lindlar catalyst. Palladium catalysts. Palladium(II) chloride. Rhodium-on-carbon. Tris(triphenylphosphine)chlotorhodium. Tris(triphenylphosphine)ruthenium dl-chloride. Urushibara catalysts. 

Complexes of the type [Ir(bzn)(cod)(L)](C104) (bzn = benzonitrile L = tricyclohexylphosphine, neomenthyldiphenylphosphine) catalyze the homogeneous hydrogenation of tetrasubstituted prochiral amido alkenes R R C=CR N. Under very mild conditions, the catalysis occurs for N = NHCOR, R = COjMe R = R = Me, R" = Me, Ph R = Me, R- = Ph, R = Me, Ph R = Ph, R = Me, R = Ph. [Ir(cod)(PCy3)(py)](PFg) serves as a catalyst in the hydroxyl-directed hydrogenation of cyclic and acyclic alkenic alcohols, wherein the reaction shows diastereoselectivity dependent on catalyst substrate stoichiometry. Park el have noted that the iridium(I)... 

Prochiral unsaturated carboxylic acids present an anomaly, since some of the best examples of their asymmetric hydrogenation require monophosphine-derived catalysts. An early example using Morrison s neomenthyldiphenylphosphine, (35), is shown and in a wide-ranging study respectable optical yields were obtained. In reduction of (36) and... 

The selectivity for formation of the branched isomer and the activity for formation of the carboxylic acid or ester when the catalyst is generated from monodentate ligands, such as PPhj and neomenthyldiphenylphosphine, " is exceptionally high, as shown in Equation 17.34. The use of these ligands led to the development of a particularly efficient method to prepare naproxen by the Albemarle company shown in Equation 17.35. Naproxen was synthesized from 2-bromo-6-methoxynapthalene by a sequence of a Heck reaction (Chapter 19) to form the vinylnapthalene, followed by palladium-catalyzed hydrocarboxylation. Unfortunately, changes in business focus have reduced the use of this process. 

---