Practical asymmetric Henry reaction catalyzed by a chiral diamine-Cu(OAc)2 complex.
The chiral diamine ligand 3 was designed and synthesized from (R,R)-1,2-diphenylethylenediamine, (S)-2,2'-dibromomethyl-1,1'-binaphthalene, and o-xylylene dibromide. The resulting 3-Cu(OAc)2 complex was a highly efficient catalyst for the Henry reaction, giving the various nitroaldols with over 90% ee (up to >99%). The reaction was performed in n-propyl alcohol at room temperature, and the Henry adducts were produced in high yield with excellent enantiomeric excess; these attributes are desirable in a catalyst for practical use.
Arai
Takayoshi
T
Department of Chemistry, Graduate School of Science, Chiba University, Inage 263-8522, Japan. tarai@faculty.chiba-u.jp
Watanabe
Masahiko
M
Yanagisawa
Akira
A