Enantioselective Synthesis of α-Hydroxy and α-Amino Phosphonates via Catalytic Asymmetric Hydrogenation
摘要:
[GRAPHICS]Cationic rhodium catalysts of the C-2 symmetric DuPHOS (1) and BPE (2) ligands have demonstrated the ability to asymmetrically hydrogenate a novel series of enol phosphonates (3) in good to excellent enantiomeric excess under mild conditions. Initial studies toward the catalytic asymmetric hydrogenation of enamido phosphonates (6 and 7) using the DuPHOS-Rh+ catalysts are also reported.
Tuning of the Structures of Chiral Phosphane-Phosphites: Application to the Highly Enantioselective Synthesis of α-Acyloxy Phosphonates by Catalytic Hydrogenation
ligands 1 and 5 in catalytic asymmetric hydrogenations of enolphosphonates 12 demonstrated a critical influence of the steric characteristics of the phosphane-phosphite in the course of the reaction, and optimization of the two phosphorus functionalities resulted in the production of versatile and efficient catalysts for this class of hydrogenations: enantioselectivities of up to 98% ee were thus obtained
Chiral phosphine-phosphites provide versatile catalysts for the highlyenantioselectivehydrogenation of alpha-acyloxy alpha, beta-unsaturated phosphonates.
手性膦-亚磷酸酯为α-酰氧基α,β-不饱和膦酸酯的高度对映选择性氢化提供了多种催化剂。
Enantioselective Synthesis of α-Hydroxy and α-Amino Phosphonates via Catalytic Asymmetric Hydrogenation
作者:Mark J. Burk、Timothy A. Stammers、Judith A. Straub
DOI:10.1021/ol9906099
日期:1999.8.1
[GRAPHICS]Cationic rhodium catalysts of the C-2 symmetric DuPHOS (1) and BPE (2) ligands have demonstrated the ability to asymmetrically hydrogenate a novel series of enol phosphonates (3) in good to excellent enantiomeric excess under mild conditions. Initial studies toward the catalytic asymmetric hydrogenation of enamido phosphonates (6 and 7) using the DuPHOS-Rh+ catalysts are also reported.
Readily Available Chiral Phosphine−Aminophosphine Ligands for Highly Efficient Rh-Catalyzed Asymmetric Hydrogenation of α-Enol Ester Phosphonates and α-Enamido Phosphonates
[GRAPHICS]A new class of unsymmetrical hybrid phosphine-aminophosphine ligands has been prepared from commercially available, inexpensive (S)-1-phenylethylamine through a concise synthetic procedure. These ligands are not very sensitive to air and moisture, and displayed good enantioselectivities in the Rh-catalyzed asymmetric hydrogenation of various dimethyl alpha-benzoyloxyethenephosphonates bearing beta-aryl, beta-alkyl, and beta-alkoxy substituents and N-benzyloxycarbonyl alpha-enamido phosphonates, in which up to 97% ee was obtained. A side-by-side comparison study disclosed that these new phosphine-aminophosphine ligands showed better enantioselectivity than BoPhoz ligands.
Highly Enantioselective Synthesis of α-Hydroxy Phosphonic Acid Derivatives by Rh-Catalyzed Asymmetric Hydrogenation with Phosphine–Phosphoramidite Ligands