55232-22-9Relevant academic research and scientific papers
Asymmetric Hydrogenation of Olefins with Aprotic Oxygen Functionalities Catalyzed by BINAP-Ru(II) Complexes
Ohta, Tetsuo,Miyake, Tsutomu,Seido, Nobuo,Kumobayashi, Hidenori,Takaya, Hidemasa
, p. 357 - 363 (2007/10/02)
Cyclic α,β-unsaturated ketones, alkylidene lactones, and alkenyl ethers have been hydrogenated in high enantiomeric excesses by use of BINAP-Ru(II) complexes (BINAP = 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl) as catalysts. 2-Alkylidenecyclopentanones were hydrogenated in the presence of Cl, Ru2Cl4(BINAP)2(NEt3), or Ru(OCOCH3)2(BINAP) in up to 98percent ee, while in the case of 2-benzylidene- and 2-(3-phenylpropylidene)cyclopentanones, enantiomeric excesses of the hydrogenation were below 50percent under the same conditions.The sense of asymmetric induction as well as the enantioselectivity (95percent ee) obtained in the hydrogenation of (E)-2-propylidene-γ-butyrolactone were the same as those of the (Z)-isomer.Lactones, 2- and 4-alkylidene-γ-butyrolactones, were converted to the corresponding saturated γ-butyrolactones in 95percent ee.Hydrogenation of diketene with the catalytic system derived from (benzene)>Cl and triethylamine or complex Ru2Cl42(NEt3) established a new synthetic route to (R)-4-methyl-2-oxetanone, a promising monomer of biodegradable polymers, in up to 97percent selectivity and 92percent ee.Alkenyl ethers, 2-methylenetetrahydrofuran, and 2-methyl-3,4-dihydrofuran have also been hydrogenated to give 2-methyltetrahydrofuran in 91 and 87percent ee, respectively.
Asymmetric Synthesis of 2-Substituted Butyrolactones and Valerolactones
Meyers, A. I.,Yamamoto, Yukio,Mihelich, Edward D.,Bell, Richard A.
, p. 2792 - 2796 (2007/10/02)
The use of chiral oxazolines 1, 2, 5, and 8 under asymmetrically induced alkylation conditions gave α-substituted oxazolines 3, 6, 9, and 13 which were hydrolyzed to α-substituted butyro- and valerolactones 4 and 11.Either enantiomer of the lactones could be prepared in predictable absolute configuration by reversing the order of alkyl group introduction.The lactones were prepared in 60-86 percent enantiomeric excess which was determined by either chemical correlation or high-pressure liquid chromatography of the diastereomers 10.
