Sidearm effect: improvement of the enantiomeric excess in the asymmetric Michael addition of indoles to alkylidene malonates.
A pseudo-C3-trisoxazoline was designed and synthesized. The improvement of the traditional bisoxazoline into a novel trisoxazoline by a sidearm approach resulted in highly catalytic enantioselective Michael addition of indoles to alkylidene malonates. Excellent catalytic reactivity and enantioselectivity (up to 99% yield and 93% ee) were achieved.
Zhou
Jian
J
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 200032 Shanghai, China.
Tang
Yong
Y