Modular synthesis of chiral homo- and heterotrisoxazolines. Improving the enantioselectivity in the asymmetric Michael addition of indole to benzylidene malonate.
A simple approach to a diverse set of chiral trisoxazolines is described. Deprotonation of bisoxazolines 2, followed by treatment of 2-chloromethyloxazolines 3, affords chiral trisoxazolines, including chiral homo- and hetero-trisoxazolines in good to high yields. These trisoxazolines are successfully applied in the asymmetric reaction of indole with benzylidene malonate, and ee's up to 93% were obtained.
Ye
Meng-Chun
MC
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, 354 Fenglin Lu, Shanghai 200032, China.
Li
Bin
B
Zhou
Jian
J
Sun
Xiu-Li
XL
Tang
Yong
Y