Sequence of Intramolecular Carbonylation and Asymmetric Hydrogenation Reactions: Highly Regio- and Enantioselective Synthesis of Medium Ring Tricyclic Lactams was written by Lu, Shui-Ming;Alper, Howard. And the article was included in Journal of the American Chemical Society in 2008.Category: chiral-phosphine-ligands This article mentions the following:
The intramol. cyclocarbonylation reaction of (aminoaryloxy)-functionalized arylalkynes and analogs I (X = N, CH, CCl; Y = O, NMe, OCH2, OCH2CH2; R1 = H, Me, OMe, CN, CF3, Cl, MeCO; R2 = H, Me, CO2Me; R3 = H, Cl, Me, CO2Me) with palladium-complexed dendrimers on silica is a very effective method for the regioselective synthesis of methylene 8-, 9-, and 10-membered rings II. The heterogeneous dendritic catalysts were easily recovered by simple filtration and reused for up to 10 cycles with only a slight loss of activity. Asym. hydrogenation of the resulting unsaturated heterocycles II afforded optically active tricyclic lactams III in excellent yields and in high enantiomeric excess. This process can tolerate a wide array of functional groups, including halide, ether, nitrile, ketone, and ester. Moreover, the variation of heteroatom on the rings does not have any influence on the efficiency and enantioselectivity of the reaction. In the experiment, the researchers used many compounds, for example, (2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2Category: chiral-phosphine-ligands).
(2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2) belongs to chiral phosphine ligands. During the past two decades, tertiary phosphine catalysts have been applied extensively in a wide range of carbon–carbon and carbon–heteroatom bond-forming transformations. Chiral ligands coordinate to metal centers to create an asymmetric environment around the reaction centers, which eventually affects enantioselectivity and reaction rate.Category: chiral-phosphine-ligands
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis