Enantioselective construction of vicinal tetrasubstituted stereocenters by the mannich reaction of silyl ketene imines with isatin-derived ketimines.
A highly enantioselective Mannich reaction of silyl ketene imines with isatin-derived ketimines has been realized by using a chiral N,N'-dioxide/Zn(II) catalyst. A variety of β-amino nitriles containing congested vicinal tetrasubstituted stereocenters were obtained with excellent outcomes (up to 98 % yield, >19:1 d.r. and 99 % ee). Based on the experimental investigations, a possible transition state has been proposed to explain the origin of the asymmetric induction.
Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064 (China).
Jiannan
J
Zhao
Bing
B
Fang
Weiwei
W
Luo
Xiaoyu
X
Hao
Xiaohua
X
Liu
Lili
L
Lin
Xiaoming
X
Feng
D000586:Amination; D002384:Catalysis; D005030:Ethylenes / Q000737:chemistry*; D007097:Imines / Q000138:chemical synthesis* / Q000737:chemistry; D007659:Ketones / Q000737:chemistry*; D009570:Nitriles / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D015032:Zinc / Q000737:chemistry*
D005030:Ethylenes; D007097:Imines; D007659:Ketones; D009570:Nitriles; C542835:ketimine; D015032:Zinc; C008223:ketene
asymmetric synthesis; heterocycles; homogeneous catalysis; synthetic methods; zinc