Asymmetric Synthesis of Pyrazolone Fused Spirocyclohexeneimines via a Vinylogous Michael/Cyclization Cascade Reaction. Issue 1 (28th November 2018)

• Record Type: Journal Article
• Authors: Meninno, Sara; Mazzanti, Andrea; Lattanzi, Alessandra
• Is Part Of: Advanced synthesis & catalysis. Volume 361:Issue 1(2019)
• Page Start: 79
• Page End: 84
• Publication Date: 2018-11-28
• Subjects: asymmetric synthesis -- organocatalysis -- spirocyclic compounds -- dicyanoalkenes -- cascade reactions; Catalysis -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Chemistry -- Periodicals; Chemistry, Technical -- Periodicals; Chemistry -- Periodicals; Catalysis -- Periodicals; Technology, Pharmaceutical -- Periodicals; 547.2
• DOI: 10.1002/adsc.201801337
• Languages: English
• ISSNs: 1615-4150

Abstract

Abstract: Diastereoisomeric pyrazolone‐fused spirocyclohexenimines, bearing contiguous all‐carbon quaternary and tertiary stereocenters, are readily synthesized for the first time in good to excellent yield (up to 98%) and high enantioselectivity (up to 97% ee) via vinylogous Michael reaction/cyclization cascade reaction of α‐arylidene pyrazolones and α, α‐dicyanoalkylidenes. The formal [4+2] atom‐economical annulation proceeds with commercially available Takemoto's catalyst under mild reaction conditions. Scale‐up reaction and post‐transformation of the products were also demonstrated. Abstract :