P-Chirogenic diaminophosphine oxide: a new class of chiral phosphorus ligands for asymmetric catalysis.
We successfully synthesized a novel P-chirogenic diaminophosphine oxide 4, which was applied to catalytic enantioselective construction of quaternary carbon centers using Pd-catalyzed asymmetric allylic substitution with various beta-keto esters (up to 99% yield, 94% ee). Preliminary mechanistic studies indicated that two molecules of 8 coordinate to the Pd metal in a monodentate fashion, resulting in the formation of Pd complex 9 (Pd:8 = 1:2), which functions as the active species.
Nemoto
Tetsuhiro
T
Graduate School of Pharmaceutical Sciences, Chiba University, Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
Matsumoto
Takayoshi
T
Masuda
Takamasa
T
Hitomi
Tsukasa
T
Hatano
Keiichiro
K
Hamada
Yasumasa
Y