Chiral amine/chiral acid as an excellent organocatalytic system for the enantioselective tandem oxa-Michael-aldol reaction.
The asymmetric tandem oxa-Michael-aldol reaction of salicylic aldehyde derivatives with alpha,beta-unsaturated aldehydes catalyzed by a chiral amine/chiral acid organocatalytic system was investigated. The organocatalytic system of (S)-diphenylpyrrolinol trimethylsilyl ether with chiral shift reagent (S)-Mosher acid presented a synergistic effect in the improvement of reaction performance and offered an efficient steric effect in the transformation. The tandem oxa-Michael-aldol reaction proceeded with high yields (up to 90%) and with excellent ee values (up to 99%) to give the corresponding chromene derivatives. The structure of the chiral ammonium salt formed in situ and the corresponding mechanism were also studied by (1)H NMR.
Luo
Shu-Ping
SP
State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou, China.
Li
Zhao-Bo
ZB
Wang
Li-Ping
LP
Guo
Yi
Y
Xia
Ai-Bao
AB
Xu
Dan-Qian
DQ
D000447:Aldehydes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D013237:Stereoisomerism; D013379:Substrate Specificity
D000447:Aldehydes; D000588:Amines; C116609:3-hydroxybutanal