A construction of the pentacyclic framework of sterepolide is described. Stereochemistry of the structure 2 is well established by unequivocal reaction sequences. The Diels-Alder adducts are transformed into a key intermediate 15 by a few steps. Conversion of 15 to 2 is effected by a Nazarov cyclization and subsequent selective reduction of the lactone carbonyl group.
描述了sterepolide五环骨架的构造。结构2的立体
化学通过明确的反应序列得到很好的确立。 Diels-Alder 加合物通过几个步骤转化为关键中间体 15。 15至2的转化是通过纳扎罗夫环化和随后内酯羰基的选择性还原来实现的。