Homochiral cycloadducts derived from sugar aldoximes via nitrone intermediates
摘要:
Tandem nitrone generation/cycloaddition reactions between simple sugar aldoximes and divinyl sulphone in refluxing toluene have been shown to occur regiospecifically and with high diastereoselectivity in the cycloaddition step to afford homochiral cycloadducts in good yield. The process is applicable to both furanose and pyranose aldoximes. Absolute stereochemistries of the products have been determined by NOE spectroscopy and X-ray crystallography.
Homochiral cycloadducts derived from sugar aldoximes via nitrone intermediates
摘要:
Tandem nitrone generation/cycloaddition reactions between simple sugar aldoximes and divinyl sulphone in refluxing toluene have been shown to occur regiospecifically and with high diastereoselectivity in the cycloaddition step to afford homochiral cycloadducts in good yield. The process is applicable to both furanose and pyranose aldoximes. Absolute stereochemistries of the products have been determined by NOE spectroscopy and X-ray crystallography.
Carbocyclic ring closure of hex-5-enopyranosides and pent-4-enofuranosides: a nitrile oxide approach
作者:John K. Gallos、Theocharis V. Koftis
DOI:10.1039/b007654f
日期:——
Nitrile oxide cycloadditions to protected enopyrano(furano)sides derived from D-glucose and D-ribose afford spiro-isoxazolines in good yield and high diastereoselectivity, which upon Raney Nickel hydrogenation in MeOH–AcOH (6∶1) undergo N–O bond cleavage followed by spontaneous aldol-like condensation to give good yields of hydroxylated six- and five-membered cyclic enaminones as the main products
Tandem nitrone generation/cycloaddition reactions between simple sugar aldoximes and divinyl sulphone in refluxing toluene have been shown to occur regiospecifically and with high diastereoselectivity in the cycloaddition step to afford homochiral cycloadducts in good yield. The process is applicable to both furanose and pyranose aldoximes. Absolute stereochemistries of the products have been determined by NOE spectroscopy and X-ray crystallography.