870283-99-1Relevant academic research and scientific papers
Highly enantioselective chlorination of β-keto esters and subsequent SN2 displacement of tertiary chlorides: A flexible method for the construction of quaternary stereogenic centers
Shibatomi, Kazutaka,Soga, Yoshinori,Narayama, Akira,Fujisawa, Ikuhide,Iwasa, Seiji
, p. 9836 - 9839 (2012/07/30)
Highly enantioselective chlorination of β-oxo esters and subsequent stereospecific substitution of tertiary chlorides are described. Enantioselective chlorination of β-keto esters and malonates was performed using a chiral Lewis acid catalyst prepared from Cu(OTf)2 and the newly developed spirooxazoline ligand 2 to yield the desired α-chlorinated products with high enantioselectivity (up to 98% ee). Nucleophilic substitution of the resulting chlorides proceeded smoothly to afford a variety of chiral molecules such as α-amino, α-alkylthio, and α-fluoro esters, without loss of enantiopurity. The results of X-ray crystallographic analysis proved that Walden inversion occurs at the chlorinated tertiary carbon center. These results supported the fact that the substitution proceeds via an S N2 mechanism.
