Unexpected Cascade Reactions of Ortho‐Hydroxyenaminones and β, γ‐Unsaturated α‐Ketoesters to Access Hydrogenated Benzoxazolepolycycles and Pyrrole−Phenol Atropisomers. Issue 21 (4th October 2019)

• Record Type: Journal Article
• Authors: Bai, Xuguan; Wang, Lele; Zhang, Ziying; Zhang, Kuan; Bu, Zhanwei; Wu, Yufeng; Zhang, Wenjing; Wang, Qilin
• Is Part Of: Advanced synthesis & catalysis. Volume 361:Issue 21(2019)
• Page Start: 4893
• Page End: 4901
• Publication Date: 2019-10-04
• Subjects: cascade reaction -- benzoxazole -- axial chirality -- polycyclic heterocycle -- atropisomer; Catalysis -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Chemistry -- Periodicals; Chemistry, Technical -- Periodicals; Chemistry -- Periodicals; Catalysis -- Periodicals; Technology, Pharmaceutical -- Periodicals; 547.2
• DOI: 10.1002/adsc.201900950
• Languages: English
• ISSNs: 1615-4150

Abstract

Abstract: An unexpected BF3 ⋅ OEt2 ‐catalyzed Michael addition/cyclization/dehydration sequence of ortho ‐hydroxyenaminones with aromatic or aliphatic aldehyde‐derived β, γ‐unsaturated α‐ketoesters has been achieved to afford a wide range of fused hydrogenated benzoxazole polycycles in 67–95% yields in a highly diastereoselective manner. When isatin‐derived β, γ‐unsaturated α‐ketoesters were employed as substrates, completely different reactivities were observed, delivering an array of new atropisomers with an oxindole‐substituted N−C axially chiral pyrrole−phenol backbone in up to 97% yield. Moreover, DFT calculations were conducted to account for the possible reaction pathway and the stereochemistry. Abstract :