825-63-8Relevant academic research and scientific papers
Switching of enantioselectivity in the catalytic addition of diethylzinc to aldehydes by regioisomeric chiral 1,3-amino sulfonamide ligands
Hirose, Takuji,Sugawara, Kazuyuki,Kodama, Koichi
, p. 5413 - 5428 (2011/08/05)
Twenty chiral 1,3-amino sulfonamides of two classes (2a-i and 3a-k) have been prepared from (-)-cis-2-benzamidocyclohexanecarboxylic acid (1) and studied as ligands for catalytic enantioselective addition of Et2Zn to a variety of aromatic and aliphatic aldehydes. The ligands 2 and 3 are regioisomers in which the position of the amine and sulfonamide groups is exchanged. Each class of ligands with the same chirality was shown to afford sec-alcohols with the opposite stereochemistry. Structural surveys revealed that the combination of tertiary amino and p-toluenesufonylamido groups works most effectively for the reaction. Through optimization of the structural and reaction conditions, the best ligands quantitatively provided both enantiomeric secondary alcohols in good to excellent enantioselectivity of up to 94% and 98% ee for (S)- and (R)-enantiomers, respectively.
Synthesis of chiral 1,3-diamines derived from cis-2- benzamidocyclohexanecarboxylic acid and their application in the Cu-catalyzed enantioselective Henry reaction
Kodama, Koichi,Sugawara, Kazuyuki,Hirose, Takuji
, p. 13584 - 13592 (2012/01/03)
In this study, 13 different chiral 1,3-diamines were synthesized from (-)-cis-2-benzamidocyclohexanecarboxylic acid. They were successfully applied as ligands in the Cu-catalyzed asymmetric Henry reaction between benzaldehyde and nitromethane. It was conf
