[reaction: see text] A fully substrate controlled stereoselective route to construct cis-hexahydronaphthalene 4 is described starting from nonracemic butenolide 6. The key step is an exo-selective transannular Diels-Alder reaction (TADA) of tetraene 5, whose intrinsic constraint allows selective formation of one stereodefined product. Compound 4 is a key intermediate in the synthesis of the novel antibiotic
[反应:参见正文]从非外消旋的
丁烯内酯6开始,描述了一种完全由底物控制的立体选择性途径来构建顺式六氢
萘4。关键步骤是四烯5的外选择性跨环Diels-Alder反应(T
ADA),其内在约束使得选择性地形成一种立体定义的产物。化合物4是合成新型抗生素布
雷尼霉素(1)的关键中间体。