A practical and efficient synthesis of the C-16-C-28 spiroketal fragment (CD) of the spongistatins
A practical and efficient synthesis of the C-16-C-28 spiroketal fragment (CD) of the spongistatins
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DOI：
10.1021/ol035848h
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发表时间：
2003-12-11
期刊：
影响因子：
5.2
通讯作者：
Ley, SV
中科院分区：
文献类型：
--
作者：
Gaunt, MJ;Hook, DF;Ley, SV
[图片]报道了一种实用而有效的途径来获得海绵抑制素的CD螺旋状（C-16-C-28）。两个立体中心由手性构件引入，其余的由底物控制的变换引入。关键的-酮-1,3-二硫烷中间体是由二硫醇偶联加成到炔上产生的，c环上的1,3-二硫烷单元在螺旋酮化和随后的外映异构反应中起关键作用。该合成需要24步，其中最长的线性序列为19步，总产率为14.5%（为最长的线性序列）。
[GRAPHICS]A practical and efficient route to the CD spiroketal (C-16-C-28) of the spongistatins is reported. Two stereocenters are introduced from chiral building blocks with the remainder introduced by substrate-controlled transformations. The key beta-keto-1,3-dithiane intermediate is generated by a dithiol conjugate addition to an ynone and the 1,3-dithiane unit in the C-ring plays a key role in the spiroketalization and subsequent epimerization. The synthesis requires 24 steps, with a longest linear sequence of 19 steps in an overall yield of 14.5% (for the longest linear sequence).