Binap-silver salts as chiral catalysts for the enantioselective 1,3-dipolar cycloaddition of azomethine ylides and alkenes
作者:Juan Mancebo-Aracil、María Martín-Rodríguez、Carmen Nájera、José M. Sansano、Paulo R.R. Costa、Evanoel Crizanto de Lima、Ayres G. Dias
DOI:10.1016/j.tetasy.2012.10.015
日期:2012.12
Binap-AgSbF6 catalyzed 1,3-dipolarcycloadditions between azomethineylides and electrophilicalkenes are described and compared with analogous transformations mediated by other Binap-silver(I) salt complexes. Maleimides and 1,2-bis(phenylsulfonyl)ethylene are suitable dipolarophiles for obtaining very good enantioselectivities, even better values are generated by a multicomponent version. There are
New Chiral Ferrocenyl P,S-Ligands for Highly Diastereo-/Enantioselective Catalytic [3 + 2] Cycloaddition of Azomethine Ylides with Cyclic and Acyclic Enones
developed and successfully applied in a highly endo-selective catalytic asymmetric cycloaddition of azomethine ylides with various enones, including cyclic and acyclic α-enones. For cyclic α-enones, a [Cu(CH3CN)4]ClO4/(Rc,SFc)-2f complex catalyzed the cycloaddition to give the sole endo-cycloadducts in perfect enantioselectivities (normally 99% ee), while an AgOAc/(Rc,SFc)-2f catalytic system exhibited good