Synthesis of <i>N</i>‐Glycoside Analogs via Thionolactones
作者:Wendong Wang、Pornpun Rattananakin、Peter G. Goekjian
DOI:10.1081/car-120026472
日期:2003.12.31
Indolyl N-glycoside analogs were obtained by a two-step sequence via indole N-thioamides. Treatment of thionobutyrolactone with indolylmagnesium bromide provides the corresponding indole N-thioamide. The use of 10:1 toluene:THF as solvent is important in favoring N- over C3-acylation. Treatment of the omega-hydroxythioamide with 2 equiv of Meerwein's reagent followed by sodium borohydride gives the corresponding N-(tetrahydrofuranyl)indole. Addition of carbon nucleophiles gives access to ketose nucleoside analogs, while activation of the omega-hydroxyl group can give access to tetrahydrothiophene N-glycosides.
Highly Diastereoselective Samarium Diiodide Induced Ketyl Cyclisations of Indole and Pyrrole Derivatives - Scope and Limitations
Here we summarise our results for SmI2-induced 5-exo-trig to 8-exo-trig reductive cyclisations of suitably substituted indole and pyrrole derivatives. All precursors were easily prepared by simple N-alkylation or N-acylation of indole and pyrrole derivatives with the corresponding iodo alkanones, acid chlorides or lactones. The SmI2-induced cyclisations in most cases provided tri- and tetracyclic derivatives