well affording the corresponding aza-Diels-Alder product in high yield with up to 91% ee at room temperature. The present catalytic enantioselective reaction of imines provided an effective route to opticallyactive nonproteinogenic alpha-amino acids. The products of the catalytic enantioselective aza-Diels-Alder reaction of the cyclic dienes can be used for the preparation of key compounds such as natural
A formal synthesis of (±)-aristeromycin starting from the imino Diels-Alder cycloadduct 3a has been achieved with high overall yield. A novel method for the in situ preparation of N-sulfonylimines is reported.
The use of two optically active N-sulfinyl α-imino esters in the stereoselective aza-Diels–Alder reaction
作者:Trygve Andreassen、Marianne Lorentzen、Lars-Kristian Hansen、Odd R. Gautun
DOI:10.1016/j.tet.2009.01.090
日期:2009.4
Diastereoselective aza-Diels–Alder (aza-DA) reactions of ethyl (S)-N-(tert-butanesulfinyl)iminoacetate (2a) and ethyl (S)-N-(p-toluenesulfinyl)iminoacetate (2b) with different dienes including activated, non-activated, cyclic, and acyclic dienes in the presence of Lewis acids are described. Reactions with 2a were found to be more selective. Reactions of unactivated dienes (acyclic and cyclic) with