212890-89-6Relevant academic research and scientific papers
4,4′-Disubstituted L-prolines as highly enantioselective catalysts for direct aldol reactions
Gu, Liuqun,Yu, Menglong,Wu, Xiaoyu,Zhang, Yazhu,Zhao, Gang
, p. 2223 - 2228 (2007/10/03)
A new series of 4,4′-disubstituted prolines (1a-h) has been developed and tested as organocatalysts in the direct catalytic asymmetric aldol reaction of several aliphatic ketones with aldehydes. Catalyst 1g affords the best enantioselectivities for this transformation. The reaction was carried out in DMF using a catalyst loading of 10 mol% at -10°C to give the aldol products in up to 97% ee for acetone. In the cases of cyclohexanone and cyclopentanone, the corresponding anti-products were obtained in 94% ee.
Asymmetric Alkylation of N-Toluenesulfonylimines with Dialkylzinc Reagents Catalyzed by Copper-Chiral Amidophosphine
Soeta, Takahiro,Nagai, Kazushige,Fujihara, Hidetaka,Kuriyama, Masami,Tomioka, Kiyoshi
, p. 9723 - 9727 (2007/10/03)
The synthetic procedure of a chiral amidophosphine ligand 5 bearing two bulky substituents, 2,4,6-trimethylphenylmethyl or 2,4,6-triisopropylphenylmethyl groups, on the pyrrolidine ring was improved by employing the borane-THF reduction of the lactam-alco
An external chiral amidophosphine ligand for asymmetric conjugate addition of organocopper
Nakagawa, Yuichi,Kanai, Motomu,Nagaoka, Yasuo,Tomioka, Kiyoshi
, p. 10295 - 10307 (2007/10/03)
Two types of external, chiral amidophosphine ligands, 1-5, were prepared. Examination of their behavior in an asymmetric conjugate addition reaction of organocuprate revealed the possibility for steric tuning to realize high selectivity.
