Studies on tandem transesterification and intramolecular cycloaddition of nitrones. 2. Sequential bicyclization of α,α-dialkoxycarbonylnitrones with allyl alcohols
作者:Osamu Tamura、Toshiyuki Okabe、Tatsuya Yamaguchi、Junko Kotani、Kentoku Gotanda、Masanori Sakamoto
DOI:10.1016/0040-4020(94)00873-s
日期:1995.1
s with 1.5 equiv. of allyl alcohols in the presence of 0.1 equiv. of titanium tetrachloride and molecular sieves 4A causes tandem transesterification, E,Z-isomerization of the nitrone moieties, and intramolecular 1,3-dipolar cycloaddition to furnish bicyclic compound having ester group at the bridge head position. These reactions rarely give double transesterification product due to high reactivity
1.5当量处理α,α-烷氧羰基硝酮。在0.1当量存在下的烯丙醇 四氯化钛和分子筛4A的混合物引起串联的酯基转移,硝酮部分的E,Z-异构化和分子内的1,3-偶极环加成,以提供在桥头位置具有酯基的双环化合物。由于中间体作为偶极的高反应性而不是酯交换反应性,因此这些反应很少产生双酯交换产物。