Improved large-scale synthesis of phenylisoserine and the taxol C-13 side chain
作者:Michael V Voronkov、Alexander V Gontcharov、Zhi-Min Wang
DOI:10.1016/s0040-4039(02)02434-6
日期:2003.1
Dihydrodihydroxycinnamic acids and their esters react with acetonitrile or benzonitrile in the presence of sulfuric acid to afford the corresponding syn-β-amino-α-hydroxypropionic acid derivatives. High yields and diastereoselectivity of this transformation allows preparation of various phenylisoserine derivatives on a practical scale.
AbstractΔ2‐Thiazolines are interesting heterocycles that display a wide variety of biological characteristics. They are also common in chiral ligands used for asymmetric syntheses and as synthetic intermediates. Herein, we present asymmetric routes to 2,4,5‐trisubstituted Δ2‐thiazolines. These Δ2‐thiazolines were synthesized from readily accessible/commercially available α,β‐unsaturated methyl esters through a Sharpless asymmetric dihydroxylation and an O→N acyl migration reaction as key steps. The final products were obtained in good yields with up to 97 % enantiomeric excess.