Enantioselective Synthesis of Imidazolines with Quaternary Stereocenters by Organocatalytic Reaction of N-(Heteroarenesulfonyl)imines with Isocyanoacetates

Abstract

An organocatalytic enantioselective Mannich-type reaction of isocyanoacetate with N-sulfonylimines catalyzed by chiral thioureas derived from quinine yielded 2-imidazolines with high diastereo- and enantioselectivities (up to >99:1 dr. and 96% ee). This reaction provided a convenient route to access various imidazolines and related α,β-diamino acids having a quaternary carbon center in high enantiomeric purities.

Catalytic Isonitrile Insertions and Condensations Initiated by RNC–X Complexation

“…(26)]. [51] Extensive optimization identified the requirement for the pyridylsulfonyl imine 39b suggesting a two point binding between the catalyst and the pyridine and imine nitrogens. The reaction tolerates diverse substituents in the imine, with an aromatic substituent R 1 in the isonitrile affording the best stereoselectivity.…”

Organocatalytic Enantioselective Aza‐Friedel–Crafts Reaction of Cyclic Ketimines with Pyrroles using Imidazolinephosphoric Acid Catalysts

“…[14,15] Futhermore, we have reported the first organocatalytic aza-Friedel-Crafts reaction of imines,d erived from aldehydes, with non-protected pyrroles. [16] Herein our ongoing interestw as extended to the enantioselective aza-Friedel-Crafts reaction of 2-substituted-3H-indol-3-onesa sk etimines with non-protected pyrroles using our original organocatalysts ( Figure 2).…”

Catalytic Enantioselective Reaction of α‐Aminoacetonitriles Using Chiral Bis(imidazoline) Palladium Catalysts

“…Ther eaction of 2a with 1a using 4a/AgOAc afforded the product 3a in high yield with moderate syn selectivity but with low enantioselectivity (entry 1). [13] Therefore we attempted to use the N-(2-pyridinesulfonyl)imine 1d.The reaction of 1dafforded the product 3d in high yield with high diastereo-and enantioselectivity (entry 7). When the substituent on the imidazoline was changed to a2 ,4,6trimethylphenyl group,t he reaction gave 3a with good diastereoselectivity and excellent enantioselectivity.A s ar esult, the bis(imidazoline) 4b was found to be the best catalyst (entry 2).…”