Phosphine‐Catalyzed Asymmetric [4+2] Annulation of Vinyl Ketones with Oxindole‐Derived α,β‐Unsaturated Imines: Enantioselective Syntheses of 2′,3′‐Dihydro‐1′H‐spiro[indoline‐3,4′‐pyridin]‐2‐ones

Abstract

A novel asymmetric [4+2] annulation of vinyl ketones with oxindole-derived a,b-unsaturated imines has been developed in the presence of a multifunctional thiourea-phosphine catalyst derived from a natural amino acid, providing the first phosphine-catalyzed enantioselective synthesis of 2',3'dihydro-1'H-spiro[indoline-3,4'-pyridin]-2-ones in good yields with excellent stereoselectivities under mild conditions.

Applications of Chiral Phosphine‐Based Organocatalysts in Catalytic Asymmetric Reactions

“…Very recently, Shi′s group envisioned that isatin‐based spiro‐fused six‐membered heterocyclic skeletons with two stereocenters could be constructed through the [4+2] annulation of vinyl ketones with oxindole‐derived α,β‐unsaturated imines 37. They screened a series of chiral phosphines and found that amino‐acid‐derived chiral thiourea‐phosphine 49 was the best catalyst for this reaction.…”

“… Enantioselective [4+2] annulation of vinyl ketones with oxindole‐derived α,β‐unsaturated imines 37. TMS=trimethylsilyl.…”

Phosphine Organocatalysis for the Synthesis of Spirocyclic Compounds

“…Scheme 61 A plausible mechanism for the tandem Rauhut-Currier/ Michael/Rauhut-Currier reaction Shi, Wei and co-workers synthesized 2′,3′-dihydro-1′H-spiro[indoline-3,4′-pyridin]-2-one derivatives, starting from oxindole-derived α,β-unsaturated imines and methyl vinyl ketone 57 A. Voituriez et al…”

Stereoselective synthesis and applications of spirocyclic oxindoles

“…356 Wei and Shi developed a [4 + 2]-cycloaddition of vinyl ketones and α,β-unsaturated imines derived from isatins catalysed by a bifunctional asymmetric phosphorus-thiourea catalyst (Scheme 72, R = 2,4,6-triisopropyl phenyl). 357 In metalmediated approaches, gold catalysed spirocyclisation of in situ generated indoles and isatins was reported by Subba Reddy. 358 Related to Liu and Feng's reaction (ref.…”