Intramolecular 4+3 cycloadditions. Vinylthionium ions from allylic alcohols
作者:Michael Harmata、Darin E. Jones
DOI:10.1016/0040-4039(95)02391-7
日期:1996.2
Aldehyde 9 can be prepared from ethyl pyruvate in several steps. Treatment of 1 with various diene-containing Grignard reagents results in the formation of the corresponding allylic alcohol in good yield. Exposure of these alcohols to triflic anhydride results in the formation of 4+3 cycloadducts in good to excellent yields. Furan and simple butadiene trap the intermediate allylic cation efficiently in
醛9可以由丙酮酸乙酯分几步制备。用各种含二烯的格氏试剂处理1会导致以高收率形成相应的烯丙醇。这些醇暴露于三氟甲磺酸酐导致形成4 + 3环加合物,收率好至极好。呋喃和简单的丁二烯有效地捕获了5,7稠合环系统的形成,有效地捕获了中间烯丙基阳离子。束缚的噻吩仅进行分子内Friedal-Crafts烷基化。