Enantioselective Rh-Catalyzed Hydrogenation of 3-Aryl-4-phosphonobutenoates with a P-Stereogenic BoPhoz-Type Ligand
摘要:
A series of chiral 3-aryl-4-phosphonobutyric acid esters were synthesized in high enantioselectivities (93-98% ee) via the Rh-catalyzed asymmetric hydrogenation of the corresponding 3-aryl-4-phosphonobutenoates using a P-stereogenic BoPhoz-type phosphine-aminophosphine ligand. The methodology has been successfully applied to the asymmetric synthesis of a potential GABA(B) antagonist, (R)-phaclofen, in high enantioselectivity.
Dramatic Effect of γ-Heteroatom Dienolate Substituents on Counterion Assisted Asymmetric Anionic Amino-Cope Reaction Cascades
作者:Pradipta Das、Michael D. Delost、Munaum H. Qureshi、Jianhua Bao、Jason S. Fell、Kendall N. Houk、Jon T. Njardarson
DOI:10.1021/jacs.1c00745
日期:2021.4.21
appear to proceed via the same pathway as the fluoride albeit with the added twist of a 3-exo-trig cyclization to yield chiral cyclopropane products with three stereocenters. When this same class of nucleophiles is substituted with a γ-nitro group, the Mannich-initiated cascade is now diverted to a β-lactam product instead of the amino-Cope pathway. These anionic asymmetric cascades are solvent- and counterion-dependent
A series of chiral 3-aryl-4-phosphonobutyric acid esters were synthesized in high enantioselectivities (93-98% ee) via the Rh-catalyzed asymmetric hydrogenation of the corresponding 3-aryl-4-phosphonobutenoates using a P-stereogenic BoPhoz-type phosphine-aminophosphine ligand. The methodology has been successfully applied to the asymmetric synthesis of a potential GABA(B) antagonist, (R)-phaclofen, in high enantioselectivity.