Organocatalytic Enantioselective Synthesis of Chiral Spiro‐indoline‐pyrazolones through a formal [4+1] Annulation Reaction of 4‐Bromopyrazolones and aza‐ortho‐Quinone Methides

2024/03/06 by Laura Carceller‐Ferrer, Carlos Rodríguez‐Arias, Marc Montesinos‐Magraner +6 · 6 citations
Chemistry · #Annulation #Asymmetric Synthesis and Catalysis #Axial and Atropisomeric Chirality Synthesis #Catalysis #Chemistry #Combinatorial chemistry #Enantioselective synthesis #Indoline #Organic chemistry #Organocatalysis #Pyrazolones #Quinone #Stereochemistry #Synthesis of Indole Derivatives

paper · open access · doi:10.1002/hlca.202400029

published in Helvetica Chimica Acta 107(4) (Wiley)

openalex publication_date 2024/03/06 · openalex created_date 2024/03/07 · openalex updated_date 2026/07/20

Abstract

Abstract In this communication, a straighforward asymmetric synthesis of spiro‐indoline‐pyrazolone compounds is described. This methodology consists in a formal [4+1] cycloaddition reaction of 4‐bromopyrazolones and aza‐ ortho ‐quinone methides generated in situ catalyzed by a bisquinine‐derived squaramide in CHCl 3 under basic conditions. A variety of chiral spirocyclic compounds bearing a pyrazolone and an indoline moieties were obtained in moderate to good yields (up to 68 %) and moderate to excellent enantioselectivities (up to 93 % ee).

Related

• Asymmetric [4 + 3] cycloaddition of hydroxyphenyl indolinones to synthesize novel spirooxindoles
• Synthesis of chiral spiro-heterocyclic azides via asymmetric [4 + 2]-cycloaddition of conjugated vinyl azides
• Asymmetric Syntheses of Oxindole and Indole Spirocyclic Alkaloid Natural Products
• Stereoselective one-pot synthesis of spiro-indenoquinoxaline–pyrrolidine hybrids: structural elucidation and biological evaluation
• Catalytic Enantioselective α‐Ethynylation of Oxindoles: Total Synthesis of (‐)‐Corynoxine, (‐)‐Isorhynchophylline, (‐)‐Aspidospermidine, and (‐)‐Limaspermidine