Glycosylidene Carbenes. Part 13. Synthesis and thermolysis of representative 1-azi-glycoses
作者:Andrea Vasella、Christian Witzig、Christian Waldraff、Peter Uhlmann、Karin Briner、Bruno Bernet、Luigi Panza、Ren� Husi
DOI:10.1002/hlca.19930760811
日期:1993.12.15
compatible with the hypothesis of a heterolytic cleavage of a CN bond. An early transition state is evidenced by the absence of torsional strain by an annulated 1,3-dioxane ring. Thermolysis of 1 in MeCN at 23° led mostly to the diasteroisomeric (Z,Z)-, (E,E)-, and (E,Z)-lactone azines 56, 57, and 58 (Scheme 6), which convert to 56 under mild conditions, and to 59 (3%). The benzyloxyglucal 59 was obtained
在假设alkoxydiazirines的热解(在postlating CN键的异裂的上下文中方案1)中,我们报告了diazirines的制备4,5,7,和8,对于在diazirines的MeOH中热解的动力学参数1和4–9以及它们在非质子环境中的热解产物。的diazirines 4,57,和8(方案2-5)从已知的半缩醛制备10,19,34(从制备31(以改进的方式),并根据已建立的方法42。肟11,20,35,和43分别从相应的半缩醛作为(得到E / Z)-mixtures; 43是与环状羟胺一起形成44。氧化11,35,和43(Ñ氯琥珀酰亚胺/ 1,8-二氮杂双环[5.4.0]十一碳-7-烯(NCS / DBU)或的NaIO 4),得到(的良好的产率Ž)-hydroximolactones 12,36和45,而肟20导致产生(E)-和(Z)-氢氧内酯21和22的混合物,其采用不同的构象