1.
Org Biomol Chem
; 14(41): 9751-9759, 2016 Oct 18.
Artigo
em Inglês
| MEDLINE
| ID: mdl-27714233
RESUMO
Novel C2-symmetric N,N'-bis-[(pyrrolidin-2-yl)methyl-squaramide] TFA salts bearing (R,R)- or (S,S)-1,2-di(pyridin-2-yl)ethane spacer groups were synthesized and applied, in combination with TEA, as efficient organocatalysts for asymmetric reactions between cyclohexanone derivatives and ß-nitrostyrenes to afford the corresponding Michael adducts in high yields with good to excellent enantioselectivity. The catalytic procedure is readily scalable and recyclable over four times without a negative impact on the selectivity of the reaction. Some of the prepared compounds are valuable precursors to useful bioactive molecules.