however, under these conditions 2-deoxy-α-D-arabino-hexopyranosyl fluoride triacetate is also formed in ca. 7% yield. The Br2/AgF reagent has also been reacted with several 3,4-dihydro-2H-pyran derivatives and with other glycals. In all cases the major product(s) corresponds to the trans addition of "BrF". Similar results are obtained for the addition of the elements of "I...
当
溴与 1 在
氟化银和合适的溶剂存在下反应时,“BrF”元素顺利添加到
D-葡糖三乙酸酯 (1) 中。该反应得到主要产物 2-
溴-2-脱氧-α-D-
吡喃
甘露糖基
氟三乙酸酯,以及少量的 2-
溴-2-脱氧-α-
D-吡喃葡萄糖基
氟三乙酸酯和相应的 β-D-异头异构体. 这些产物的结构已通过
氟和质子磁共振研究阐明,并通过若干独立合成得到证实。当从 N-
溴代琥珀
酰亚胺和 HF 原位生成“BrF”时,获得了相同的三种产物;然而,在这些条件下,2-脱氧-α-D-阿拉伯-
吡喃己糖基
氟三乙酸酯也会在大约形成。7% 的收率。Br2/AgF 试剂也与几个 3 反应,4-二氢-
2H-吡喃衍
生物和其他
糖类。在所有情况下,主要产品对应于“BrF”的反式添加。添加“I ...