Intramolecular Diels–Alder reaction leading to tricyclic derivatives as intermediates of natural products synthesis
作者:Junichi Shiina、Shigeru Nishiyama
DOI:10.1016/s0040-4020(03)01013-5
日期:2003.8
Tricyclic compounds 4a and 4b possessing a bicyclo[4.3.0] moiety, were successfully synthesized by using the intramolecular Diels–Alder reaction. The siloxy- rather than acyloxy-substituents increased the ratio of the endo-cylcoadducts 10 and 12. The oxygen substitution of 9 influenced conformation of the transition state, which was stereochemically restricted by the butenolide moiety. In addition
具有双环[4.3.0]部分的三环化合物4a和4b是通过分子内Diels-Alder反应成功合成的。甲硅烷氧基取代基而不是酰氧基取代基增加了内酰基共轭加合物10和12的比例。9的氧取代影响过渡态的构象,该构象在化学上受到丁烯内酯部分的限制。另外,带有羟基的9b也以与9a相似的比例产生10b。化合物11是唯一的外型-adduct中的所有条目的产生。