Tetrahedron

Cycloadditions of substituted benzopyran-4-ones to electron-rich dienes: a new route to xanthone derivatives

PJ Cremins, ST Saengchantara, TW Wallace

文献索引：Cremins, Peter J.; Saengchantara, Suthiweth T.; Wallace, Timothy W. Tetrahedron, 1987 ,  vol. 43,  # 13  p. 3075 - 3082

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被引用次数: 61

摘要

The benzopyranones 1 and 3 reacted with 2, 3-dimethyl-1, 3-butadiene in the presence of titanium (IV) chloride to give the corresponding (4+ 2) cycloadducts 8 and 11, the former undergoing facile deformylation to give 9 and 10. Compounds 1, 3, and 4 underwent efficient uncatalysed cycloaddition to 1-methoxy-3-(trimethylsilyloxy)-l, 3-butadiene 12 to give the respective adducts 13, 14, and 18 as mixtures of Cl stereoisomers. Heating the 3- ...