Asymmetric synthesis of homoproline derivatives via Rh(I)-catalyzed hydrogenation using chiral bisphosphines as ligands was written by Zhang, Yong Jian;Park, Jung Hwan;Lee, Sang-gi. And the article was included in Tetrahedron: Asymmetry in 2004.Name: (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine) This article mentions the following:
It has been demonstrated for the first time that Rh(I)-catalyzed asym. hydrogenation of cyclic β-enamino acid derivatives I [R1 = Me, R2 = Me (1a), OBu-t, OEt; R1 = Et, R2 = Me] using chiral bisphosphines could be a highly efficient synthetic method for optically active homoproline derivatives The enantioselectivity and conversion yield were largely dependent upon the chiral ligand. Using Me-BDPMI which forms a seven-membered metal chelate, the N-acetylated β-enamino acid Me ester 1a was hydrogenated to give optically active homoproline derivative II with 100% conversion and 96% ee. In the experiment, the researchers used many compounds, for example, (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine) (cas: 37002-48-5Name: (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine)).
(((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine) (cas: 37002-48-5) belongs to chiral phosphine ligands. Phosphine-catalyzed asymmetric reactions are now powerful and versatile tools for the construction of C–C, C–N, C–O, and C–S bonds and for the syntheses of functionalized carbocycles and heterocycles. Chiral phosphine catalysts: Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates.Name: (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine)
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis