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Catalytic Asymmetric Aza‐Diels–Alder Reaction of Ketimines and Unactivated Dienes
Author(s) -
Zhao Qun,
Li Yao,
Zhang QingXia,
Cheng JinPei,
Li Xin
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202104788
Subject(s) - enantioselective synthesis , diels–alder reaction , catalysis , chemistry , yield (engineering) , phosphoric acid , aryl , combinatorial chemistry , organic chemistry , diene , materials science , alkyl , natural rubber , metallurgy
The enantioselective aza‐Diels–Alder reaction is efficient for constructing chiral tetrahydropyridines, but the catalytic asymmetric aza‐Diels–Alder reaction of ketimines with unactivated dienes is still a challenging topic. Herein, guided by computational screening, a highly enantioselective aza‐Diels–Alder reaction of 2‐aryl‐3 H ‐indol‐3‐ones with unactivated dienes was realized by using a B(C 6 F 5 ) 3 /chiral phosphoric acid catalyst system under mild conditions. The reaction has a broad scope with respect to both aza‐Diels–Alder reaction partners and hence offers rapid access to an array of tetrahydropyridine derivatives with pretty outcomes (up to 99 % yield, >20:1 dr and 98:2 er). The reaction is very efficient: lowering catalyst loadings for the model reaction to 0.1 mol %, enantioselectivity is still maintained. The synthetic utility was confirmed by transformations of the products. DFT calculations provide convincing evidence for the interpretation of stereoselection.