The widespread applications of atropisomeric compounds have led to an increasing demand for their synthesis. Rather than synthesizing different functionalized atropisomers individually, an attractive alternative is to identify a key intermediate or precursor that can be readily elaborated and functionalized to realize divergent synthesis of this class of compounds. Building on our previous research on asymmetric ring-opening of cyclic diaryliodoniums, in this work we developed a copper-catalyzed enantioselective ring-opening reaction of ortho,ortho’-dibromo substituted cyclic diaryliodonium with lithium iodide. The resulting optically active product 2,2'-dibromo-6,6'-diiodo-1,1'-biphenyl, possessing two C—Br bonds and two C—I bonds, can be selectively advanced to form different functionalities. Remarkably, the utilities of the product were highlighted by successively demonstrating C—I and C—Br metalation, followed by carboxylation, boroylation, oxygenation, allylation, phosphinylation, etc., all of which provide a new and convenient approach to synthesizing a range of functionalized axially chiral biphenyls.

中文翻译：

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光学活性 2,2'-二溴-6,6'-二碘-1,1'-联苯的制备：用于模块化合成功能化阻转异构体的强大前体†

阻转异构化合物的广泛应用导致对其合成的需求不断增加。一个有吸引力的替代方案不是单独合成不同的功能化阻转异构体，而是确定可以轻松加工和功能化的关键中间体或前体，以实现此类化合物的不同合成。基于我们先前对环状二芳基碘鎓不对称开环的研究，在这项工作中，我们开发了邻位，邻'-二溴取代的环状二芳基碘鎓与碘化锂的铜催化对映选择性开环反应。所得光学活性产物2,2'-二溴-6,6'-二碘-1,1'-联苯具有两个C-Br键和两个C-I键，可以选择性地推进以形成不同的官能团。值得注意的是，该产品的实用性通过先后演示了C-I和C-Br金属化，然后是羧化、硼酰化、氧化、烯丙基化、膦酰化等，所有这些都为合成一系列化合物提供了一种新的、便捷的方法。功能化的轴向手性联苯。