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Asymmetric Construction of Spiropyrazolone Skeletons via Amine‐Catalyzed [3+3] Annulation
Author(s) -
Leng HaiJun,
Li QingZhu,
Zeng Rong,
Dai QingSong,
Zhu HongPing,
Liu Yue,
Huang Wei,
Han Bo,
Li JunLong
Publication year - 2018
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.201701035
Subject(s) - chemistry , iminium , enantioselective synthesis , amine gas treating , annulation , organocatalysis , catalysis , combinatorial chemistry , organic chemistry , stereochemistry
Here we report a secondary amine‐catalyzed, highly enantioselective [3+3] cyclization reaction of α‐alkylidene pyrazolinones and α,β‐unsaturated aldehydes, which facilely delivers a variety of enantioenriched spiropyrazolones showing structural and stereochemical complexity. The reaction uses an iminium ion activation strategy to activate both the β‐ and ipso ‐positions of the enals as dielectrophilic sites. A broad range of substrates are compatible with this mild reaction system.