Sc3+-catalyzed aldol-type additions of N-benzoylcyclopropanecarboxamides via iodide-mediated ring-opening: stereoselective synthesis of gamma-lactams.
A new catalytic aldol-type addition of cyclopropanecarboximides to aldehydes via iodide-mediated ring-opening is presented. The reaction was found to be catalyzed at 0 degrees C using either a Sc(OTf)3/NaI system or ScI3. Stereoselective formation of alpha,alpha-disubstituted enolates occurred in situ. gamma-Lactams bearing alpha-carbonyl quaternary stereocenters were obtained in 97-57% yield and dr = 90:10-80:20 after ring closure.
Wiedemann
Sean H
SH
Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, Japan.
Noda
Hidetoshi
H
Harada
Shinji
S
Matsunaga
Shigeki
S
Shibasaki
Masakatsu
M
D000577:Amides / Q000737:chemistry*; D002384:Catalysis; D007454:Iodides / Q000737:chemistry*; D007769:Lactams / Q000138:chemical synthesis*
D000577:Amides; D007454:Iodides; D007769:Lactams