Enantiospecific Synthesis of the Phospholipase A<sub>2</sub> Inhibitor (−)-Cinatrin B
作者:Anthony N. Cuzzupe、Romina Di Florio、Mark A. Rizzacasa
DOI:10.1021/jo016221k
日期:2002.6.1
stereocenter at C2 was introduced via a chelation-controlled addition of the Grignard reagent derived from trimethylsilylacetylene to alpha-hydroxy ketone 6. Transformation of the terminal alkyne into the methyl ester 21 followed by acetal hydrolysis and selective lactol oxidation afforded cinatrin B methyl ester (22). Base hydrolysis and acid-induced relactonization then gave (-)-cinatrin B (2).
描述了从D-阿拉伯糖衍生物9首次合成磷脂酶A2(PLA2)抑制剂(-)-cinatrin B(2)的对映体。螺内酯系统是由烯丙酯8的Ireland-Claisen重排,然后进行水解和立体选择性碘内酯化而形成的。通过烯丙基醇片段中的不对称性来控制重排的立体选择性。酯(S)-8分别以73∶27的比例高产率地得到所需的重排产物7和差向异构体13。通过螯合控制地将衍生自三甲基甲硅烷基乙炔的格利雅试剂加入到α-羟基酮6中,引入C2的最终立体中心。将末端炔烃转化为甲酯21,然后进行乙缩醛水解和选择性的乳糖醇氧化,得到肉桂酸B甲酯。 (22)。