General asymmetric hydrogenation of alpha-branched aromatic ketones catalyzed by TolBINAP/DMAPEN-ruthenium(II) complex.
[reaction: see text] A catalyst system consisting of RuCl2[(S)-tolbinap][(R)-dmapen] and t-C4H9OK in 2-propanol effects asymmetric hydrogenation of arylglyoxal dialkylacetals to give the alpha-hydroxy acetals in up to 98% ee. Hydrogenation of racemic alpha-amidopropiophenones under dynamic kinetic resolution predominantly gives the syn alcohols in up to 99% ee and >98% de, while the reaction of racemic bezoin methyl ether gives the anti alcohols in excellent stereoselectivity.
Arai
Noriyoshi
N
Division of Chemical Process Engineering, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan.
Ooka
Hirohito
H
Azuma
Keita
K
Yabuuchi
Toshio
T
Kurono
Nobuhito
N
Inoue
Tsutomu
T
Ohkuma
Takeshi
T