Bis(imidazolidine)pyridine-NiCl2 Catalyst for Nitro-Mannich Reaction of Isatin-Derived N-Boc Ketimines: Asymmetric Synthesis of Chiral 3-Substituted 3-Amino-2-oxindoles
摘要:
An (S,S)-diphenyldiamine-derived bis(imidazolidine)-pyridine (PyBidine)-NiCl2 complex catalyzed the nitro-Mannich reaction of isatin-derived N-Boc ketimines to construct a chiral quaternary aminocarbon center at the C3 position of oxindoles in yields of up to 99% with 95% ee.
Bis(imidazolidine)pyridine-NiCl2 Catalyst for Nitro-Mannich Reaction of Isatin-Derived N-Boc Ketimines: Asymmetric Synthesis of Chiral 3-Substituted 3-Amino-2-oxindoles
摘要:
An (S,S)-diphenyldiamine-derived bis(imidazolidine)-pyridine (PyBidine)-NiCl2 complex catalyzed the nitro-Mannich reaction of isatin-derived N-Boc ketimines to construct a chiral quaternary aminocarbon center at the C3 position of oxindoles in yields of up to 99% with 95% ee.
An efficient asymmetric aza-Henryreaction of isatin-derived ketimines has been achieved by using a chiral guanidine–amide organocatalyst. A series of 3-substituted 3-amino-2-oxindoles was obtained with excellent results (up to 99% yield, 94% ee). Other functionalized derivatives were also conveniently transformed. This metal-free system was convenient, practical, and insensitive to air and moisture
A series of bifunctional asymmetric phase-transfercatalysts bearing multiple hydrogen-bonding donors derived from cinchona alkaloids are synthesized, and successfully applied to asymmetric nitro-Mannich of isatin-derived N-Boc ketimines. The products 3-substituted 3-amino-oxindoles were constructed in excellent yields (96–99%) and good enantioselectivities (up to 95% ee).