Premium
Unexpected Cascade Reactions of Ortho ‐Hydroxyenaminones and β,γ‐Unsaturated α‐Ketoesters to Access Hydrogenated Benzoxazolepolycycles and Pyrrole−Phenol Atropisomers
Author(s) -
Bai Xuguan,
Wang Lele,
Zhang Ziying,
Zhang Kuan,
Bu Zhanwei,
Wu Yufeng,
Zhang Wenjing,
Wang Qilin
Publication year - 2019
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201900950
Subject(s) - atropisomer , chemistry , pyrrole , phenol , isatin , aldehyde , yield (engineering) , oxindole , benzoxazole , organic chemistry , catalysis , stereochemistry , medicinal chemistry , materials science , metallurgy
An unexpected BF 3 ⋅ OEt 2 ‐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.