Variously substituted 1-alkoxycarbonyl-1, 2-dihydropyridine compounds derived from corresponding alkylpyridines were utilized as building blocks for synthesizing alkaloids containing a piperidine ring. These dihydro derivatives were submitted to the sensitized photooxygenation, followed by a novel ring-opening reaction of the endoperoxides formed here, with nucleophiles such as trimethylsilyl enol ethers or indole in the presence of stannous chloride. 1-Alkoxycarbonyl-2, 6-dialkyl-1, 2, 3, 6-tetrahydro-3-pyridinols and 1-benzyloxycarbonyl-6- (3-indolyl) -4, or 5- (2-methyl-1, 3-dioxan-2-yl) -1, 2, 3, 6-tetrahydro-3-pyridinol were obtained as stereochemically definite compounds and these were applied to the total synthesis of
Sedum alkaloids, sedacryptine and sedinine, a horsetail alkaloid, palustrine, and indole alkaloids, epiuleine and vindorosine, as important starting materials.
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