aβ-methyl-5(6H)-indanone was resolved via the hydrogen phthalate-brucine salt. The dextrorotatory enantiomer (+)4 was then converted in a 5-step stereospecific total synthesis to the important BCD tricyclic intermediate (−)13. The synthesis also adds additional proof for the absolute configuration of the bicyclic keto alcohol (+)4 by correlation with (±_13, a known degradation product of natural steroids
通过
邻苯二甲酸氢溴酸氢溴酸盐拆分(±)7,7a-二氢-1β-羟基-7aβ-甲基-5(6H)-
茚满酮。然后将右旋对映异构体(+)4在5步立体定向总合成中转化为重要的BCD
三环中间体(-)13。该合成还通过与(±_ 13)已知的天然类
固醇降解产物的相关性,为双环酮醇(+)4的绝对构型提供了额外的证据。