An asymmetric synthesis of carboxylic acid derivatives, including lactic acid and α-amino acid derivatives, from optically active 1-chlorovinyl p-tolyl sulfoxides and ester lithium enolates with creation of chirality at the α-position
作者:Masahiro Kido、Shimpei Sugiyama、Tsuyoshi Satoh
DOI:10.1016/j.tetasy.2007.07.033
日期:2007.8
out with an ester enolate generated from excess carboxylic acid tert-butyl ester with LDA in the presence of HMPA, the diastereomer of the adduct was obtained. By using the two reaction conditions for the generation of the ester enolate, a new method for asymmetric synthesis of both enantiomers of carboxylic acid derivatives having a substituent at the α-position from the one chiral source, (R)-(−)-chloromethyl
光学活性的1-氯乙烯基的治疗p -甲苯基亚砜,这是从对称的酮合成或甲酸甲酯和(- [R )- ( - ) -氯甲基p -甲苯基砜在三个步骤中,与锂羧酸的烯醇叔丁基酯,得到在α-位置具有取代基(烷基,烷氧基或二苄基氨基)的光学活性加合物,从硫手性中心有较高的1,4-手性诱导。将加合物转化为在α位具有手性中心的旋光酯,乳酸和α-氨基酸衍生物。当该加成反应与由过量羧酸叔胺生成的酯烯酸酯进行时在HMPA存在下,用LDA-丁酸酯与LDA反应,得到加合物的非对映异构体。通过使用两个反应条件生成酯烯酸酯,一种新方法可以从一个手性源(R)-(-)-氯甲基不对称合成在α-位具有取代基的羧酸衍生物的两个对映体获得了对甲苯基亚砜。