(2S,3R)-2-Benzyloxy-4-(tert-butyl-diphenyl-silanyloxy)-3-hydroxy-butyric acid methyl ester

4-ethyl 1-methyl [2S,2(1R)]-2-[2-(tert-butyldiphenylsilyl)oxy-1-[3-(methoxymethoxy)propionyl]oxyethyl]-3-diazo-2-hydroxybutanediote