The synthesis of the macrolactone 23 is described. The synthesis features a diastereoselective hydroboration of the chiral alkene 17 followed by a Suzuki cross-coupling reaction with the benzoate 5. The resulting seco acid 21 was converted to the macrolactone 23 by a Mitsunobu lactonization using immobilized triphenylphosphine. The stereogenic centers in the alkene 17 were established by a Noyori reduction
描述了大内酯23的合成。该合成的特征在于手性烯烃17的非对映选择性氢
硼化,然后与
苯甲酸酯5进行Suzuki交叉偶联反应。使用固定的
三苯基膦通过Mitsunobu内酯化将所得的
癸二酸21转化为大内酯23。烯烃17中的立体异构中心是通过Noyori还原β-
酮酸酯8和Evans aldol反应建立的。该合成说明了通过反转含甲基中心将顺式羟醛产物转化为相应的反产物。