(Pi-allyl)palladium complexes bearing diphosphinidenecyclobutene ligands (DPCB): highly active catalysts for direct conversion of allylic alcohols.
The (pi-allyl)palladium complex bearing an sp2-hybridized phosphorus ligand (DPCB-OMe: 1,2-bis(4-methoxyphenyl)-3,4-bis[(2,4,6-tri-tert-butylphenyl)phosphinidene]cyclobutene) efficiently catalyzes direct conversion of allylic alcohols in the absence of activating agents of alcohols such as Lewis acids. N-Allylation of aniline proceeds at room temperature to afford monoallylated anilines in 90-97% yields. C-Allylation of active methylene compounds is also successful at 50 degrees C using a catalytic amount of pyridine as a base, giving monoallylation products in 85-95% yields. The catalytic mechanism involving hydrido- and (pi-allyl)palladium intermediates has been proposed on the basis of stoichiometric examinations using model compounds of presumed intermediates.
Ozawa
Fumiyuki
F
Department of Applied Chemistry, Graduate School of Engineering, Osaka City University, Osaka 558-8585, Japan. ozawa@a-chem.en-g.osaka-cu.ac.jp
Okamoto
Hideyuki
H
Kawagishi
Seiji
S
Yamamoto
Shogo
S
Minami
Tatsuya
T
Yoshifuji
Masaaki
M