Aromatic Amide‐Derived Non‐Biaryl Atropisomers as Highly Efficient Ligands in Silver‐Catalyzed Asymmetric Cycloaddition Reactions

Abstract

The synthesis of a series of aromatic amide-derived non-biaryl atropisomers with a phosphine group and multiple stereogenic centers is reported. The novel phosphine ligands exhibit high diastereo- and enantioselectivities (up to >99:1 d.r., 95-99 % ee) as well as yields in the silver-catalyzed asymmetric [3+2] cycloaddition of aldiminoesters with nitroalkenes, which provides a highly enantioselective strategy for the synthesis of optically pure nitro-substituted pyrrolidines. In addition, the experimental results with regard to the carbon stereogenic center as well as the amide stereochemistry confirmed the potential of hemilabile atropisomers as chiral ligand in catalytic asymmetric [3+2] cycloaddition reaction.

Catalytic Enantioselective Synthesis of Highly Functionalized Pentafluorosulfanylated Pyrrolidines

“…Dry THF and CH 2 Cl 2 were obtained by drying over sodium/benzophenone and CaH 2 respectively, followed by distillation. Ligand L 3 was prepared according to the literature . All azomethine ylide precursors 2 were synthesized according to the literature .…”

Application of aromatic amide‐derived atropisomers as chiral solvating agents for discrimination of optically active mandelic acid derivatives in 1H nuclear magnetic resonance spectroscopy

“…In this work, four Xing‐Phos ligands, Syn ‐( S , R s), Anti ‐( S , R s), Syn ‐( R , R s), and Anti ‐( R , R s), were respectively synthesized according to the protocol described in the literature. [ 28 ] Unfortunately, the chemical durability of the CSA ( Anti ‐( R , R s)) is worse than the other three CSAs.…”

Stereochemical diversity in pyrrolidine synthesis by catalytic asymmetric 1,3-dipolar cycloaddition of azomethine ylides

“…These sulfinyl phosphine ligands afforded excellent levels of exo diastereoselectivity and enantioselectivity in the silver catalyzed exo-selective 1,3-dipolar cycloaddition of iminoesters and nitroalkenes (Scheme 6). 22 O The applicability of Xing-Phos ligand (10) was efficiently extended to other dipolarophiles such as chalcones and the less reactive methyl cinnamates (Scheme 7…”