Stereoselective Total Synthesis of (−)-Spirofungin A by Utilising Hydrogen-Bond Controlled Spiroketalisation
作者:John E. Lynch、Shannon D. Zanatta、Jonathan M. White、Mark A. Rizzacasa
DOI:10.1002/chem.201002501
日期:2011.1.3
The stereoselective total synthesis of the spiroketal containing Streptomyces metabolite (−)‐spirofungin A (1) is described. A key step involved a spiroketalisation controlled by an intramolecular H‐bond which favoured the desired spiroketal 4 (13:1 ratio). The presence of the intramolecular H‐bond in 4 is possibly due to a 1,5‐alkyne–oxygen interaction. Other key steps include an efficient cross‐metathesis
描述了含有链霉菌代谢产物(-)-螺旋真菌素A(1)的spiroketal的立体选择性全合成。关键的一步涉及通过分子内H键控制的螺环化,从而有利于所需的螺环4(13:1的比例)。分子内氢键4的存在可能是由于1,5-炔烃-氧相互作用。其它关键步骤包括一个有效的交叉复分解,以形成螺缩酮前体,锡介导顺式-aldol反应和Stille交叉偶联反应来创建C22 C23键。最终的Wittig延伸,然后进行脱保护,得到(-)-螺菌ungin A(1)。