Studies for a Diastereoselective Synthesis of the Tetracyclic Diterpenic Diol Stemarin: A Model Study for a New Preparation of the Key Intermediate and the Synthesis of (+)-18-Deoxystemarin
作者:Marco Berettoni、Rinaldo Marini Bettolo、Vittorio Montanari、Teresa Prencipe、Sergio Romeo
DOI:10.1002/hlca.19910740807
日期:1991.12.11
Methods for a stereoselective preparation of compounds of type 2b, a key intermediate of a previous synthesis of the tetracyclic diterpene stemarin (la), have been tested on model compounds 5a, 5c, and 8a. Thus, (±)-(1RS,6SR,8SR,11SR)-hydroxytricyclo[6.2.2.0l,6]dodecan-9-one (5a) was transformed by the Mitsunobu reaction into (±)-(1RS,6SR,8SR,11RS)-11-(benzoyloxy)tricyclot[6.2.2.01,6]dodecan-9-one
立体选择制备2b型化合物的方法,该化合物是模型化合物5a,5c和8a上先前合成的四环二萜Stemarin(la)合成的关键中间体。因此,通过Mitsunobu反应将(±)-(1 RS,6 SR,8 SR,11 SR)-羟基三环[6.2.2.0 l,6 ] dodecan-9-one(5a)转化为(±)-(1 RS,6 SR,8 SR,11 RS)-11-(苯甲酰氧基)三环[6.2.2.0 1,6 ] dodecan-9-one(6b; 方案2)。后者也从(±)-(1 RS,6 SR,8 SR,11 RS)-11-[(4)-甲苯磺酰氧基]三环[6.2.2.0 1,6 ] dodecan-9-one(5c)获得通过在丙酮中的Et 4 N(PhCOO)的作用。化合物6b中然后转化成(±) - (1个RS,6个RS,8个RS,9个RS) -三环[6.2.2.0 1,6 ]十二烷-9-醇(8B),对