trans-diol groups, present in the pyranose ring, can be converted readily into a double bond by the triphenylphosphine-iodine-imidazole reagent in tolueneacetonitrile solution’*‘. Application of this reaction to benzyl2-benzyloxycarbonylamino-2-deoxy-a-D-glucopyranoside (1) led’ to benzyl2-benzyloxycarbonylamino-2,3,4,6tetradeoxy-6-iodo-a-D-erythro-hex-3-enopyranoside (2) in a high yield and to an unsaturated
                                    存在于
吡喃糖环中的相邻的反式
-二醇基团可以容易地通过
三苯基膦-
碘-
咪唑试剂在甲
苯乙腈溶液“ *”中转化为双键。该反应在苄基2-苄氧基羰基
氨基-2-脱氧-a
D-吡喃葡萄糖苷(1)上的应用导致苄基2-苄氧基羰基
氨基-2,3,4,6四脱氧-6-
碘-aD-赤型-己基-3-烯
吡喃侧(2)以高收率得到不饱和二
碘类似物3,该不饱和二
碘类似物3在C-3或C-4和C-6处含有
碘原子。