- Asymmetric synthesis of β-amino-α-hydroxy acids through Lewis acid-mediated addition of ketene acetal to imines
-
Asymmetric synthesis of β-amino-α-hydroxy acids, key components of medicinally important molecules including Paclitaxel, KRI-1314, amastatin, and microginin, has been attained from the aldimine coupling of chiral imines N-alkylidene-(S)- or (R)-α-methylbenzylamine with (Z)-α-methoxyketene methyltrimethylsilyl acetal, followed by demethylation, hydrogenolysis, and hydrolysis.
- Ha, Hyun-Joon,Ahn, Young-Gil,Woo, Jun-Sik,Lee, Gwan Sun,Lee, Won Koo
-
p. 1667 - 1672
(2007/10/03)
-
- Practical preparation of α-hydroxy-β-amino ester units; Stereoselective synthesis of taxol side chain and norstatine
-
An asymmetric reaction of chiral imines with α-silyloxy ketene acetals mediated by chiral boron reagents is described. The key to its success is the use of the chiral boron complex prepared in situ from (R)- or (S)-binaphthol and B(OPh)3. Both diastereomers of α-hydroxy-β-amino ester units are successfully prepared with high selectivities by the chiral boron reagents depending on the geometry of the silyl ketene acetals. The optically pure anti α-hydroxy-β-amino ester is obtained from (E)-silyl ketene acetal, while the corresponding syn α-hydroxy-β-amino ester is obtained from (Z)- silyl ketene acetal. The method can be efficiently applied to the stereoselective synthesis of taxol C-13 side chain and the norstatine family.
- Hattori, Kouji,Yamamoto, Hisashi
-
p. 2785 - 2792
(2007/10/02)
-