New Synthesis of Pyrrolidine Homoazasugars via Aminohomologation of Furanoses and Their Use for the Stereoselective Synthesis of Aza-<i>C</i>-disaccharides
作者:Alessandro Dondoni、Pier Paolo Giovannini、Daniela Perrone
DOI:10.1021/jo020252d
日期:2002.10.1
in 17% overall yields (six steps). The formyl aza-C-glycosides proved to be valuable intermediates for the synthesis of more complex derivatives. In fact, these sugar aldehydes were employed in Wittig-type coupling reactions with galactose and ribose phosphoranes to give bis-glycosylated alkenes, which upon reduction of the double bond were transformed into methylene isosteres of (1-->6)- and (1-->5)-linked
通过2-N-硫代噻唑立体选择性加成到N-上,在2,3,5-三-O-苄基呋喃糖酶的异头异构体中心引入甲酰基并用碱性氮原子取代环氧(氨基同位)苄基,N-呋喃糖基羟胺(被掩盖的N-苄基糖硝酮),然后对所得的开链加合物进行还原性脱羟基反应,然后通过氨基上的游离羟基分子内置换并从甲酰基上除去甲酰基来进行闭环噻唑环。通过将甲酰基还原为羟甲基并通过氢解除去O-和N-苄基,将所得甲酰基氮杂-C-糖苷转化为2,5-二脱氧-2,5-亚氨基己糖醇(吡咯烷高氮杂)。 。将此反应序列应用于四种呋喃糖酶(D-阿拉伯糖,D-核糖,D-lyxo,L-xylo),以17%的总收率(六个步骤)得到无羟基和氨基的纯天竺葵,包括天然产物2,5-二脱氧-2,5-亚氨基-D-甘露醇。甲酰基氮杂-C-糖苷被证明是合成更复杂衍生物的有价值的中间体。实际上,这些糖醛与半乳糖和核糖磷烷一起用于Wittig型偶联反应中,生成双糖基化的烯烃,双键还原后转化为(1->