Tandem double-Michael-addition/cyclization/acyl migration of 1,4-dien-3-ones and ethyl isocyanoacetate: stereoselective synthesis of pyrrolizidines.
Up to four adjacent stereocenters can be formed stereoselectively in the construction of a pyrrolizidine unit through a novel organocatalytic reaction that involves treatment of various dienones with ethyl isocyanoacetate (see scheme; DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene). Mechanisms for this atom-economic, one-pot synthesis have been proposed.
Tan
Jing
J
Department of Chemistry, Northeast Normal University, Changchun, 130024, PR China.
Xu
Xianxiu
X
Zhang
Lingjuan
L
Li
Yifei
Y
Liu
Qun
Q
D002384:Catalysis; D003500:Cyclization; D017953:Isocyanates / Q000737:chemistry*; D011763:Pyrrolizidine Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D017953:Isocyanates; D011763:Pyrrolizidine Alkaloids