Synthesis of Highly Condensed Polycyclic Carbohydrates by Reaction of a Spirocyclic Enamino Sulfonate Derived from <scp>d</scp>-Xylofuranose with Bifunctional Reagents
作者:Alessandra Cordeiro、María Luisa Jimeno、Miguel A. Maestro、María-José Camarasa、Ernesto Quesada、Ana San-Félix
DOI:10.1021/jo701775a
日期:2007.12.1
5-O-tosyl derivative (1), easily prepared from 1,2-O-isopropylidene-α-d-xylofuranose, serves as a useful precursor for the preparation of highly condensed cyclic carbohydrates. The synthesis involves a first cyclization of the 5-O-tosyl sugar derivative 1 to a highly reactive cyclic enamine, which subsequently undergoes the nucleophilic attack of a bifunctional reagent X(CH2)nZ in a regio- and stereospecific
容易地由1,2 - O-异亚丙基-α - d-木呋喃糖容易地制备的适当取代的5- O-甲苯磺酰基衍生物(1)用作制备高稠合的环状碳水化合物的有用前体。合成过程包括将5- O-甲苯磺酰基糖衍生物1首次环化为高反应性环状烯胺,该烯胺随后经历双功能试剂X(CH 2)n的亲核攻击Z以区域和立体定向方式。最后,自发的环化步骤允许形成与糖主链融合的立体化学定义的额外环。这个环的官能化和尺寸可通过双官能试剂的适当选择而变化。对其中一种碳水化合物进行了X射线衍射分析和深入的NMR研究,以突出这些化合物的应变性质。