1149755-74-7Relevant articles and documents
Controlling stereoselectivity in the aminocatalytic enantioselective mannich reaction of aldehydes with in situ generated N-carbamoyl imines
Galzerano, Patrizia,Agostino, Dario,Bencivenni, Giorgio,Sambri, Letizia,Bartoli, Giuseppe,Melchiorre, Paolo
experimental part, p. 6069 - 6076 (2010/09/07)
A simple and convenient method for the direct, aminocatalytic, and highly enantioselective Mannich reactions of aldehydes with in situ generated N-carbamoyl imines has been developed. Both α-imino esters and aromatic imines serve as suitable electrophilic components. Moreover, the judicious selection of commercially available secondary amine catalysts allows selective access to the desired stereoisomer of the N-tert-butoxycarbonyl (Boc) or N-carbobenzyloxy (Cbz) Mannich adducts, with high control over the syn or anti relative configura-tion and almost perfect enantioselectivity. Besides the possibility to fully control the stereochemistry of the Mannich reaction, the main advantage of this method lies in the operational simplicity; the highly reactive N-carbamate-protected imines are generated in situ from stable and easily handled aamido sulfones. 2010 Wiley-VCH Verlag GmbH & Co. KGaA.
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
supporting information; experimental part, 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.
