A Short Path Synthesis of a-Hydroxy Ester from Aldehyde Using (1-Ethoxy-vinyl)lithium and Its Application to the Syntheses of Thymine Polyoxin C and Uracil Polyoxin C

A short path synthesis of the a-hydroxy esters (4 and 5) from the aldehyde (3) using (I-ethoxyviny1)lithium and its application to the total syntheses of the pyrimidine nucleoside, thymine polyoxin C (1) and uracil polyoxin C (2), are described.Polyoxins are an important class of peptidyl nucleoside antibiotics isolated Gom the culture broths of Streptomyces cacaoi var.asoerrsis, which are potent competitive inhibitors of chitin synthetase of a variety of phytopathogenic fungi.1According to recent studies, polyoxins arc also reported to inhibit chitin synthetase of Carrdidu ulbicms, a medically important human fungal pathogen.2AU members of thc polyoxin family bear the 1-(5-amino-5-deoxy-~-D-aIlofuranun~nosyl)pyrimidines such as thymine polyoxin C (I) and urdcil polyoxin C (2) as a basic component.A variety of chemical syntheses of amino acid nucleosides (1 and 2 ) have been reported over the years,3 one of the most important intermediate for the general synthesis of them appeared to he (R)-a-hydroxy ester