PyBidine-Cu(OTf)<sub>2</sub>-Catalyzed Asymmetric [3+2] Cycloaddition with Imino Esters: Harmony of Cu-Lewis Acid and Imidazolidine-NH Hydrogen Bonding in Concerto Catalysis
(PyBidine)–Cu(OTf)2 complex catalyzing the endo‐selective [3+2] cycloaddition of nitroalkenes with imino esters was applied to the reaction of methyleneindolinones with imino esters to afford spiro[pyrrolidin‐3,3′‐oxindole]s in up to 98 % ee. X‐ray crystallographic analysis of the PyBidine–Cu(OTf)2 complex and DFT calculations suggested that an intermediate Cu enolate of the imino ester reacts with
PyBidine–Ni(OAc)<sub>2</sub>-Catalyzed Michael/Aldol Reaction of Methyleneindolinones and Thiosalicylaldehydes for Stereochemically Divergent Thiochromanyl-spirooxindoles
作者:Takayoshi Arai、Tomoya Miyazaki、Hiroki Ogawa、Hyuma Masu
DOI:10.1021/acs.orglett.6b02783
日期:2016.11.18
(S,S)-Diphenylethylenediamine-derived bis(imidazolidine)pyridine (PyBidine)–Ni(OAc)2 complex catalyzed the asymmetric Michael/aldolreaction of methyleneindolinone and thiosalicylaldehyde to produce (2′R,3S,4′R)-thiochromanyl-spirooxindole having three contiguous stereogenic centers.
Highly enantio- and diastereoselective construction of spirocyclic oxindoles via a palladium-catalyzed decarboxylative asymmetric [4 + 2] annulation strategy
A palladium-catalyzed decarboxylative asymmetric [4 + 2] annulation of methyleneindolinones with a zwitterionic oxo-1,4-dipole intermediate was successfully developed to access spirocyclic oxindoles bearing two vicinal stereocenters in good yields with high diastereoselectivities and enantioselectivities. This strategy features a broad substrate scope (28 examples), allowing for efficient scale-up