The mechanism of the hydroxyl → halogen exchange reaction in the presence of triphenylphosphine, N-bromosuccinimide, and N,N-dimethylformamide: application of a new Vilsmeier-type reagent in carbohydrate chemistry
作者:György Hodosi、Benjamin Podányi、János Kuszmann
DOI:10.1016/0008-6215(92)84042-q
日期:1992.6
Abstract Triphenylphosphine reacts with N -bromosuccinimide to give a phosphonium salt ( 13 ), which reacts with N,N -dimethylformamide to afford N,N -dimethylsuccinimidomethaniminium bromide ( 16 ). The latter product reacts with an alcohol to give an O -forminimium compound 17 , and, in the presence of an alcohol, 13 is transformed into an alkoxyphsphonium intermediate ( 14 ). Both 14 and 17 can
摘要三苯基膦与N-溴丁二酰亚胺反应生成a盐(13),该盐与N,N-二甲基甲酰胺反应生成N,N-二甲基琥珀酰亚胺化亚氨基溴化铵(16)。后者产物与醇反应得到O-甲亚胺化合物17,并且在醇存在下,将13转化为烷氧基an中间体(14)。14和17都可以通过加热转化为烷基溴。水解17得到相应的O-甲酰基衍生物。1.2:5.6-二-O-异亚丙基-α-d-葡萄糖呋喃糖与13或16的反应生成6-溴-6-脱氧-1,2:3,5-二-O-异亚丙基-α-d-葡萄糖呋喃糖和建议了这些反应的可能机理。一种制备3-deoxy-3-halogeno-1,2:5的有效方法,