The total synthesis of the biaryl ether natural product violaceic acid (1) in four steps is described. The steps included a S_NAr reaction between phenol 7 and flouroarene 12 to afford the biaryl ether 13, selective reduction of a nitro group to an amine in the presence of an aldehyde, a Cu mediated Sandmeyer reaction and final hydrolysis to afford the target compound 1. The amine 14 was also converted into the known iodide 18 which gave impure 1 on Pd mediated hydroxide cross coupling.

中文翻译：

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紫草酸的四步合成

描述了四个步骤中的联芳基醚天然产物紫胶酸（1）的全合成。这些步骤包括苯酚7与氟芳烃12之间的S _N Ar反应以提供联芳醚13，在醛存在下将硝基选择性还原为胺，Cu介导的Sandmeyer反应以及最终水解以提供目标化合物1。胺14也被转化为已知的碘化物18，其在Pd介导的氢氧化物交叉偶联上得到不纯的1。