Highly enantioselective sequential hydrogenation of ethyl 2-oxo-4-arylbut-3-enoate to ethyl 2-hydroxy-4-arylbutyrate.
The hydrogenation of (E)-ethyl 2-oxo-4-arylbut-3-enoate with [NH2Me2](+)[{RuCl [(S)-SunPhos]}2(mu-Cl3)] gave ethyl 2-hydroxy-4-arylbutyrate with 94-96% ee. Further investigation has proved that the hydrogenation proceeded via a sequential hydrogenation of CO and CC bonds, which is sensitive to the reaction temperature. Hydrolysis of ethyl 2-hydroxy-4-phenylbutyrate (ee 93%) provided the 2-hydroxy-4-phenylbutyric acid with 81% yield at 99% ee after a single recrystallization from 1,2-dichloroethylene.
Meng
Qinghua
Q
School of Chemistry and Chemical Technology, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240, China.
Zhu
Lufeng
L
Zhang
Zhaoguo
Z