Carboxylates as Nucleophiles in the Enantioselective Ring-Opening of Formylcyclopropanes under Iminium Ion Catalysis
作者:Estibaliz Díaz、Efraim Reyes、Uxue Uria、Luisa Carrillo、Tomas Tejero、Pedro Merino、Jose L. Vicario
DOI:10.1002/chem.201801434
日期:2018.6.21
In this work, carboxylic acids, which are typically regarded as poor nucleophiles, are demonstrated to be competent reagents to promote the ring‐opening of formylcyclopropanes after activation of the latter through iminium ion formation. Under optimized reaction conditions, a variety of γ‐acyloxy‐substituted aldehydes can be obtained in high yields and enantioselectivities through the desymmetrization
Stereoselective Synthesis of Either Exo- or Endo-3-Azabicyclo[3.1.0]hexane-6-carboxylates by Dirhodium(II)-Catalyzed Cyclopropanation with Ethyl Diazoacetate under Low Catalyst Loadings
作者:Terrence-Thang H. Nguyen、Antonio Navarro、J. Craig Ruble、Huw M. L. Davies
DOI:10.1021/acs.orglett.3c03652
日期:2024.4.12
Although cyclopropanation with donor/acceptor carbenes can be conducted under low catalyst loadings (<0.001 mol %), such low loading has not been generally effective for other classes of carbenes such as acceptor carbenes. In this current study, we demonstrate that ethyldiazoacetate can be effectively used in the cyclopropanation of N-Boc-2,5-dihydropyrrole with dirhodium(II) catalyst loadings of