1176274-00-2Relevant academic research and scientific papers
A designer axially chiral amino sulfonamide as an efficient organocatalyst for direct asymmetric anti/-selective mannich reactions and syw-selective cross-aldol reactions
Kano, Taichi,Yamaguchi, Yukako,Maruoka, Keiji
scheme or table, p. 6678 - 6687 (2010/02/28)
A direct asymmetric Mannich reaction using a novel axially chiral amino sulfonamide (S)-3 that is highly anti- and enantioselective has been developed. For instance, in the presence of a catalytic amount of (S)-3, the reactions between aldehydes and a-imino esters proceeded smoothly to give anti Mannich products with a significantly higher antilsyn ratio and enantioselectivity than previously possible. By utilizing N-Boc-protected aro-matic imines instead of a-imino esters, the synthetically useful Boc protecting group and various aromatic or heteroaromatic substituents were installed into the anti Mannich products and consequently the substrate scope of the anri'-selective Mannich reaction and the synthetic utility of the anti Mannich products have been expanded. The axially chiral amino sulfonamide (S)-3 has also been successfully applied to asymmetric direct cross-aldol reaction between two different aldehydes. The catalyst (S)-3 has the advantage of giving mainly syn products, whereas proline shows the opposite anti selectivity.
