Synthesis of 1,2-dihydropyridines using vinyloxiranes as masked dienolates in imino-aldol reactions.
[reaction: see text] The application of vinyloxiranes, substituted with an electron-withdrawing group, as masked dienolates in vinylogous imino-aldol reactions was achieved. Under the reaction conditions highly substituted 1,2-dihydropyridines were obtained in moderate to good yields. Mechanistic studies indicate that the reaction proceeds via the formation of an (E)-amino-alpha,beta-unsaturated aldehyde, followed by isomerization to the (Z)-isomer, cyclization, and elimination of a water molecule, leading to the formation of the 1,2-dihydropyridine.
Brunner
Bernhard
B
Davenport Research Laboratories, Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6.
Stogaitis
Nicole
N
Lautens
Mark
M