Electron-poor chiral diphosphine ligands: high performance for Rh-catalyzed asymmetric 1,4-addition of arylboronic acids at room temperature.
Electron-poor chiral diphosphine ligands, MeO-F(28)-BIPHEP (1a) and MeO-F(12)-BIPHEP (1b), were synthesized for controlling a transition-metal catalyst electronically. The 1b-ligated Rh catalyst showed excellent catalytic activity with high % ee for asymmetric 1,4-addition of arylboronic acids to alpha,beta-unsaturated carbonyls at 20 degrees C. The strong pi-acceptor ability of 1b induces transmetalation of arylboronic acid to catalyst precursor [RhCl(1b)](2) directly in the first step of the catalytic cycle.
Division of Chemistry and Biochemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Okayama 700-8530, Japan. korenaga@cc.okayama-u.ac.jp
Toshinobu
T
Korenaga
Kazutaka
K
Osaki
Ryota
R
Maenishi
Takashi
T
Sakai