New Synthetic Bromination Procedures for Use in Radiolabelling-Chemistry: Reaction ofC-Metallated Derivatives of Carbohydrates with Bromide, in the Presence of Mild Oxidizing Agents
作者:Jean-Richard Neeser、Laurance D. Hall、Julius A. Balatoni
DOI:10.1002/hlca.19830660403
日期:1983.6.15
triglycosylborane 1 and dicyclohexylglycosylborane 2 readily react with bromine chloride generated in situ from bromide and N-chlorosuccinimide (NCS) to give the bromo-sugar 3 (75 and 60%, resp.). The use of the BH3-THF/bromide/NCS/2 AcONa procedure permits the rapid, face-specific synthesis of 6 (58% uptake of bromine) and face-selective synthesis of 8/9 (71% uptake of bromine), from vinyl ether derivatives
在2摩尔当量的存在下。对于AcONa,三糖基硼烷1和二环己基糖基硼烷2均易于与由溴化物和N-氯代琥珀酰亚胺(NCS)原位产生的氯化溴反应,得到溴糖3(分别为75%和60%)。BH 3 -THF /溴化物/ NCS / 2 AcONa程序的使用可实现快速的面特异性合成6(溴的吸收率为58%)和面选择性合成8/9(溴的吸收率为71%),分别来自乙烯基醚衍生物5和7。二环己基硼烷/溴化物/ NCS / 2 AcONa方法可快速定量地转化11至溴糖12(91%)。硼氢化-反金属化序列使获得C-化的碳水化合物13(71%)和14(78%)成为可能。通过与一当量的溴化物/氯胺-T / HCl水溶液反应,自然裂解双(糖基)汞衍生物13,得到3(87%)和14(76%)。炔糖15的氢化锡烷基化得到(E)-锡烷基乙烯基衍生物16作为主要产物。后者的前体16被溴化物/氯胺-T / HCl水溶液试剂自发裂解,得到溴丁糖。17(96%)。