Chiral monoaminoalcohols and diaminoalcohols of squaric acid: new catalysts for the asymmetric reduction of ketones by borane
作者:Haibing Zhou、Shoumao Lü、Rugang Xie、Albert S.C Chan、Teng-Kuei Yang
DOI:10.1016/s0040-4039(00)02162-6
日期:2001.2
Two series of newchiral ligands, squaric acid aminoalcohols and C2-symmetric squaric acid diaminoalcohols have been synthesized. The chiral oxazaborolidines formed in situ from these ligands have been used in the enantioselective borane reduction of prochiral ketones and diketones to afford alcohol products with up to 99% enantiomeric excesses. The structures of the ligands have an obvious effect
This invention is generally directed to fluorinated squaraine compositions of the formula:
wherein R,. R2, R3, and R4, are independently selected from alkyl groups, containing from about 1 to about 20 carbon atoms, and layered photoresponsive devices containing such compositions.