Synthesis of diastereoisomeric 6-deoxy-d-allal- and 6-deoxy-d-galactal-derived allyl epoxides and examination of the regio- and stereoselectivity in nucleophilic addition reactions. Comparison with the corresponding 6-O-functionalized allyl epoxides
作者:Valeria Di Bussolo、Lucilla Favero、Maria Rosaria Romano、Mauro Pineschi、Paolo Crotti
DOI:10.1016/j.tet.2008.06.039
日期:2008.8
6-deoxy-d-allal- and 6-deoxy-d-galactal-derived allyl epoxides 8α and 8β have been stereoselectively prepared and their behaviour as glycosyl donors in addition reactions with nucleophiles examined and compared with that of the corresponding 6-OR (R=Bn, Tr) substituted epoxides. The completely stereoselective substrate-dependent glycosylation process found in the reaction of 8α and 8β with O-nucleophiles (alcohols
新的6-脱氧d-allal-和6-脱氧d半乳醛衍生的环氧化物烯丙基8α和8β已立体选择性地制备,并且检查,并与相应的比较它们在与亲核试剂加成反应的糖基供体行为6- OR(R = Bn,Tr)取代的环氧化物。完全立体选择性衬底依赖性糖基化方法中的反应中发现8α和8β与ö -nucleophiles(醇类和部分保护的单糖)和Ç -nucleophiles(烷基锂化合物和TMSCN),表明了6 OR基团在侧链中确定选择性不是必需的。8α和8β的反应与叠氮化物(TMSN 3,N-亲核试剂)的结合使得有可能修改先前提出的形成相应的顺式叠氮基醇(顺式-1,2-加成产物)的合理性。