Kanayama Takatoshi, Yoshida Kazumasa, Miyabe Hideto, Kimachi Tetsutaro, Takemoto Yoshiji
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
J Org Chem. 2003 Aug 8;68(16):6197-201. doi: 10.1021/jo034638f.
The asymmetric synthesis of beta-substituted alpha-amino acids with use of iridium-catalyzed allylic substitution was described. The Ir-catalyzed allylic substitution of diphenylimino glycinate with allylic phosphates proceeded smoothly even at 0 degrees C and gave branch products with high enantioselectivity (up to 97% ee), when chiral bidentate phosphite bearing the 2-ethylthioethyl group was employed. In addition, both diastereomers of the branch products were synthesized stereoselectively by simply switching the base employed. These methods were also applied to the asymmetric synthesis of quaternary alpha-amino acids.
描述了使用铱催化的烯丙基取代反应进行β-取代α-氨基酸的不对称合成。即使在0℃下，二苯基亚氨基甘氨酸酯与烯丙基磷酸酯的铱催化烯丙基取代反应也能顺利进行，当使用带有2-乙硫基乙基的手性双齿亚磷酸酯时，可得到具有高对映选择性（高达97% ee）的支链产物。此外，通过简单地改变所用的碱，可立体选择性地合成支链产物的两种非对映异构体。这些方法也应用于季铵α-氨基酸的不对称合成。
