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Catalytic Asymmetric Syntheses of Alkylidenecyclopropanes from Allenoates with Donor‐Acceptor and Diacceptor Diazo Reagents
Ist Teil von
Chemistry : a European journal, 2022-08, Vol.28 (47), p.e202201438-n/a
Ort / Verlag
Germany: Wiley Subscription Services, Inc
Erscheinungsjahr
2022
Quelle
Wiley Online Library Journals Frontfile Complete
Beschreibungen/Notizen
The first diastereo‐ and enantioselective cyclopropanation reactions of electron‐deficient allenes with donor‐acceptor and diacceptor diazo reagents are described. The desired enantioenriched alkylidenecyclopropanes (ACPs) were obtained in high yields with high diastereo‐ and enantioselectivities in the presence of Rh2((S)‐TCPTAD)4 or Rh2((R)‐BTPCP)4 catalysts (up to 95 % yield, >95 : 5 d.r. and 99 : 1 e.r.). This methodology gave a direct access to ACPs bearing multiple electron‐deficient substituents and allows to further expand the availability of ACPs chemistry. Interestingly, during the examination of the scope of this reaction, the asymmetric intramolecular C−H insertion reaction into tert‐butyl group was observed as a side reaction with up to 94 : 6 e.r.
Chiral ACPs: The catalytic asymmetric synthesis of alkylidenecyclopropanes from electron‐deficient allenes is described. The methodology, using donor‐acceptor or diacceptor diazo reagents, catalyzed by a chiral rhodium complex furnished the corresponding ACPs in high yields with excellent diastereo‐ and enantioselectivities.