Ketenacetale als dienophile: Reaktivität und regiospezifität bei (4+2)-cycloadditionen mit inversem elektronenbedarf
作者:K. Müller、J. Sauer
DOI:10.1016/s0040-4039(01)81226-0
日期:1984.1
Ketene acetales 3a–3e differ in reactivity by 5–6 powers of ten in the reaction with monoaryl tetrazines 1a–1e. While 3a–3d yield “ortho-adducts” 4 almost exclusively, the ketene-N,N-acetale 3e give both regioisomers 4 and 5, the isomer ratio is depending on the polarity of the solvent used.
在与单芳基四嗪1a-1e的反应中,乙缩醛3a-3e的反应性相差10-6的5-6次幂。3a-3d几乎完全生成“邻位加合物” 4,而烯酮-N,N-乙缩醛3e则同时生成区域异构体4和5,异构体比例取决于所用溶剂的极性。