Furuno, Hiroshi published the artcileChiral rare earth organophosphates as homogeneous Lewis acid catalysts for the highly enantioselective hetero-Diels-Alder reactions, HPLC of Formula: 297752-25-1, the publication is Tetrahedron (2003), 59(52), 10509-10523, database is CAplus.
Various trivalent rare earth chiral phosphate complexes [ML3] (L = I or II, R = H, 2,6-xylyl; M = Sc, La, Ce, Nd, Gd, Ho, Y) were prepared and evaluated as a Lewis acid catalyst for the asym. hetero-Diels-Alder reaction of aldehydes with the Danishefsky’s diene. Some of them effectively promoted the reaction at room temperature in the presence or absence of achiral additives under homogeneous conditions to afford the corresponding cycloadducts with high ee’s (up to 99% ee). During these reactions, remarkably high asym. amplifications (pos. nonlinear effects) were observed as the first example in the metal ion-chiral ligand 1:3 catalytic system. A scandium catalyst bearing the H8-BNP ligand, [ScL3] (L = II), could be recovered after the reaction and successfully reused for the next round of reactions. In addition, the hetero-Diels-Alder reaction of α-keto esters was effectively catalyzed by [YL3] (L = I, R = H) without any additives thus producing the asym. quaternary carbon in excellent enantioselectivities (up to >99% ee).
Tetrahedron published new progress about 297752-25-1. 297752-25-1 belongs to chiral-phosphine-ligands, auxiliary class Chiral Phosphoric Acids, name is (R)-4-Hydroxy-8,9,10,11,12,13,14,15-octahydrodinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide, and the molecular formula is C20H21O4P, HPLC of Formula: 297752-25-1.
Referemce:
https://en.wikipedia.org/wiki/Phosphine_ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate