Werner Complexes with -Dimethylaminoalkyl Substituted Ethylenediamine Ligands: Bifunctional Hydrogen-Bond-Donor Catalysts for Highly Enantioselective Michael Additions. Academic Article uri icon


  • The racemic carbonate complex [Co(en)2 O2 CO](+) Cl(-) (en=1,2-ethylenediamine) and (S)-[H3 NCH((CH2 )n NHMe2 )CH2 NH3 ](3+) 3Cl(-) (n=1-4) react (water, charcoal, 100C) to give [Co(en)2 ((S)-H2 NCH((CH2 )n NHMe2 )CH2 NH2 )](4+) 4Cl(-) (3a-dH(4+) 4Cl(-) ) as a mixture of / diastereomers that separate on chiral-phase Sephadex columns. These are treated with NaOH/Na(+) BArf (-) (BArf =B(3,5-C6 H3 (CF3 )2 )4 ) to give lipophilic - and -3a-d(3+) 3BArf (-) , which are screened as catalysts (10mol%) for additions of dialkyl malonates to nitroalkenes. Optimal results are obtained with -3c(3+) 3BArf (-) (CH2 Cl2 , -35C; 98-82% yields and 99-93% ee for six -arylnitroethenes). The monofunctional catalysts - and -[Co(en)3 ](3+) 3BArf (-) give enantioselectivities of <10% ee with equal loadings of Et3 N. The crystal structure of -3aH(4+) 4Cl(-) provides a starting point for speculation regarding transition-state assemblies.

published proceedings

  • Angew Chem Int Ed Engl

altmetric score

  • 0.75

author list (cited authors)

  • Ghosh, S. K., Ganzmann, C., Bhuvanesh, N., & Gladysz, J. A.

citation count

  • 48

complete list of authors

  • Ghosh, Subrata K||Ganzmann, Carola||Bhuvanesh, Nattamai||Gladysz, John A

publication date

  • March 2016