First examples of enantioselective palladium-catalyzed thiocarbonylation of prochiral 1,3-conjugated dienes with thiols and carbon monoxide: efficient synthesis of optically active β,γ-unsaturated thiol esters was written by Xiao, Wen-Jing;Alper, Howard. And the article was included in Journal of Organic Chemistry in 2001.Electric Literature of C29H30P2 This article mentions the following:
A catalyst system based on [Pd(OAc)2]/(R,R)-DIOP has been found to effect asym. thiocarbonylation of certain prochiral 1,3-dienes to produce good yields of optically enriched β,γ-unsaturated thiol esters. The reaction was performed under an atm. of carbon monoxide (400 psi) at 110°C in methylene chloride for 60 h. The asym. thiocarbonylation proceeded with good to excellent enantioselectivities (up to 89% ee). The stereoselectivity is strongly influenced by the structure of the chiral phosphine ligands and substrates, as well as by the reaction conditions. The enantiodetn. step is assumed to be CO insertion to a π-allylpalladium intermediate. In the experiment, the researchers used many compounds, for example, (2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2Electric Literature of C29H30P2).
(2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2) belongs to chiral phosphine ligands. Thousands of arylphosphines have been used as chiral ligands for metal-catalyzed asymmetric reactions. Asymmetric catalytic performance is determined not only by the metal center but also by the chiral ligand selected.Electric Literature of C29H30P2
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis