(2E,4S)-5-Acetoxy-4-formyloxy-2-pentenal (2) prepared in one step from tri-O-acetyl-D-glucal was selectively deformylated to give the α,β-unsaturated aldehyde 3 with an unprotected hydroxy group at C-4. Michael-type addition reaction of hydrazoic acid to 3 followed by acylation at C-1 gave a 1:1 mixture of the erythro- and threo-isomers of 5-O-acetyl-3-azido-1 -O-(4-biphenylcarbonyl)-2,3-dideoxypentofuranoses 4 and 5. They were used as substrates for nucleoside coupling with silylated thymine to give all four D-isomers of 3′-azido-3′-deoxythymidine 6-9.
(由三-O-乙酰基-
D-葡萄糖醛一步制备的 (2E,4S)-5-乙酰氧基-4-甲酰氧基-
2-戊烯醛(2)经选择性脱醛得到 C-4 位未受保护羟基的δ,δ-不饱和醛 3。将
苯甲酸与 3 进行迈克尔型加成反应,然后在 C-1 处进行酰化,得到了 5-O- 乙酰基-3-
叠氮-1-O-(4-
联苯羰基)-2,3-二脱氧戊
呋喃糖 4 和 5 的 1:1 红外异构体和 3-异构体混合物。它们被用作核苷与
硅烷化胸腺
嘧啶偶联的底物,从而得到 3′-
叠氮-3′-脱氧
胸苷 6-9 的所有四种 D-异构体。