116140-87-5Relevant articles and documents
Enantiotopic-Group Differentiation. Asymmetric Monoesterification of Malonic Acids Using Cinchona Alkaloid Derivatives
Hiratake, Jun,Shibata, Kayoko,Baba, Naomichi,Oda, Jun'ichi
, p. 278 - 280 (2007/10/02)
2,2-Dimethyl-5-methyl-5-phenyl-4,6-dioxo-1,3-dioxane (1) was cleaved asymmetrically, by nucleophilic attack of primary alkoxide ions, paired with N-benzylquaternary ammonium cations, derived from cinchona alkaloids, to give optically active monoalkyl malonates 3 with moderate stereoselectivity.The ester group of 3 was selectively reduced to afford optically active α-methyltropic acid (5) in good yield.The relationship between the structure of ammonium cations and the direction of stereoselectivity is described.