930278-38-9Relevant academic research and scientific papers
General asymmetric hydrogenation of α-branched aromatic ketones catalyzed by TolBINAP/DMAPEN-ruthenium(II) complex
Arai, Noriyoshi,Ooka, Hirohito,Azuma, Keita,Yabuuchi, Toshio,Kurono, Nobuhito,Inoue, Tsutomu,Ohkuma, Takeshi
, p. 939 - 941 (2007)
(Chemical Equation Presented) A catalyst system consisting of RuCl 2[(S)-tolbinap][(R)-dmapen] and t-C4H9OK in 2-propanol effects asymmetric hydrogenation of arylglyoxal dialkylacetals to give the α-hydroxy acetals in up to 98% ee. Hydrogenation of racemic α-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.
Asymmetric hydrogenation of aromatic ketones catalyzed by the TolBINAP/DMAPEN-ruthenium(II) complex: A significant effect of N-substituents of chiral 1,2-diamine ligands on enantioselectivity
Ooka, Hirohito,Arai, Noriyoshi,Azuma, Keita,Kurono, Nobuhito,Ohkuma, Takeshi
experimental part, p. 9084 - 9093 (2009/04/11)
(Chemical Equation Presented) Asymmetric hydrogenation of acetophenone in the presence of Ru(II) catalysts coordinated by TolBINAP and a series of chiral 1,2-diamines was studied. The sense and degree of enantioselectivity were highly dependent on the N-substituents of the diamine ligands. The N-substituent effect was discussed in detail. Among these catalysts, the (S)-TolBINAP/(R)- DMAPEN-Ru(II) complex showed the highest enantioselectivity. The mode of enantioface selection was interpreted by using transition state models based on the X-ray structure of the catalyst precursor. The chiral catalyst effected the hydrogenation of alkyl aryl ketones and arylglyoxal dialkyl acetals to afford the chiral alcohol in >99% ee in the best cases. Hydrogenation of racemic benzoin methyl ether with the chiral catalyst through dynamic kinetic resolution gave the anti-alcohol (syn:anti = 3:97) in 98% ee, while the reaction of α-amidopropiophenones resulted in the syn-alcohols (symanti = 96:4 to >99:1) in >98% ee.
