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Catalytic Asymmetric [8+3] Annulation Reactions of Tropones or Azaheptafulvenes with meso ‐Aziridines
Author(s) -
Zhang Jianlin,
Xiao Wanlong,
Hu Haipeng,
Lin Lili,
Liu Xiaohua,
Feng Xiaoming
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201803507
Subject(s) - desymmetrization , annulation , enantioselective synthesis , catalysis , chemistry , cycloaddition , medicinal chemistry , oxazines , stereochemistry , organic chemistry
Highly enantioselective [8+3] high‐order cycloaddition reactions of tropones or azaheptafulvenes with meso ‐aziridines were achieved by a desymmetrization/annulation process in the presence of chiral N , N′ ‐dioxide/Mg(OTf) 2 complex. The corresponding tetrahydrocyclohepta[ b ][1,4]oxazines and tetrahydro‐1 H ‐cyclohepta‐ [ b ]‐pyrazines were obtained in good yields (66–98 %) with excellent diastereo‐ and enantioselectivities (>19:1 d.r., 90–96 % ee ). A possible transition state model was proposed to elucidate the origin of chiral induction based on the control experiments and X‐ray crystal structure of the catalyst.