Alpha-aminoester-derived imidazoles by 1,5-electrocyclization of azavinyl azomethine ylides.
An efficient and practical method for the preparation of alpha-imidazol-1-yl esters from 1,2-diaza-1,3-dienes (DDs), alpha-amino esters, and aldehydes is described. The overall sequence features a Michael-type conjugate addition between the alpha-amino ester and the DD, followed by iminium ion formation via condensation with the aldehyde and 1,5-electrocyclization of the resulting thermally generated azavinyl azomethine ylide to afford eventually alpha-imidazol-1-yl esters. Such a protocol allows access to enantiomerically pure imidazoles from optically pure alpha-amino esters.
Attanasi
Orazio A
OA
Istituto di Chimica Organica, Università degli Studi di Urbino Carlo Bo, via I Maggetti 24, 61029 Urbino, Italy.
Caselli
Emilia
E
Davoli
Paolo
P
Favi
Gianfranco
G
Mantellini
Fabio
F
Ori
Claudia
C
Prati
Fabio
F