182007-01-8Relevant articles and documents
Complete chiral induction from enantiopure 1,2-diamines to benzophenone-based achiral bisphosphane ligands in noyori-type RuII catalysts
Jing, Qing,Sandoval, Christian A.,Wang, Zheng,Ding, Kuiling
, p. 3606 - 3616 (2006)
We report the design and synthesis of a novel class of RuII catalysts (3) composed of achiral benzophenone-based bisphosphane ligands and enantiopure 1,2-diamines for the asymmetric hydrogenation of aryl ketones. The developed catalysts show excellent enantioselectivities (up to 97 % ee) and activities (up to S/C = 10,000) in the hydrogenation of a variety of aromatic ketones. Complete chiral induction from the enantiopure 1,2-diamine to the achiral bisphosphane ligand was observed. The coordination of the C=O moiety in 3 to the cationic RuII center is considered to be of key importance in providing a higher thermodynamic and kinetic rotation barrier for the flexible bisphosphane ligand, resulting in the preferential formation of only one diastereomer, and thus explaining the high enantioselectivity of the catalyst. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Selective Demethylation of 1,1-Bis(5-tert-butyl-2-methoxyphenyl)ethanol with Chlorohydroalane
Yamato, Takehiko,Inoue, Hisataka,Maeda, Kenji,Tashiro, Masashi
, p. 1731 - 1745 (2007/10/03)
The action of chlorohydroalane (AlH2Cl) on 1,1-bis(5-tert-butyl-2-methoxyphenyl)ethanol (3b) in ether led to a novel demethylation reaction which afforded 1,1-bis(5-tert-butyl-2-hydroxyphenyl)ethanol (5b).Hydroalane in ether is an effective reagent for se
