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Catalytic Enantioselective Dearomatization/Rearomatization of 2‑Nitroindoles to Access 3‑Indolyl-3′-Aryl-/Alkyloxindoles: Application in the Formal Synthesis of Cyclotryptamine Alkaloids
journal contribution
posted on 2020-08-28, 20:48 authored by Wei-Cheng Yuan, Xiao-Jian Zhou, Jian-Qiang Zhao, Yong-Zheng Chen, Yong You, Zhen-Hua WangThe first catalytic
enantioselective dearomatization/rearomatization
of 2-nitroindoles triggered by the Michael addition of 3-monosubstituted
oxindoles was established. A wide range of 3-indolyl-3′-alkyloxindoles
(up to 99% yield, 97% ee) and 3-indolyl-3′-aryloxindoles (up
to 95% yield, 99% ee) were obtained by using an organocatalyst. This
method provides an unprecedented strategy to access structurally diverse
3,3′-disubstituted oxindoles bearing a sterically congested
triaryl-containing all-carbon quaternary stereocenter. The utility
of this approach was verified by the formal synthesis of cyclotryptamine
alkaloids.