An efficient and practical method was developed for the synthesis of C2‐symmetric 2,2'‐bipyridine‐α,α’‐1‐t‐butyl‐diol ligands. The disclosed synthesis involves the Ullmann homocoupling of a keto bromo‐pyridine under NiCl2/Zn/PPh3 conditions, followed by the stereoselective double hydrogen transfer to the obtained 2,2'‐bipyridine‐diketone using RuII Noyori–Ikariya catalysts. This approach allowed the successful synthesis of 2,2'‐bipyridine‐α,α'‐1‐t‐butyl‐diol, i.e (S,S)‐Bolm's ligand, with a quantitative yield and an excellent stereoselectivity (ee > 99.5%, de > 99.5%), with an overall yield of 69% from easily accessible starting materials.

中文翻译：

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通过立体选择性双氢转移至 2,2'-联吡啶二酮高效合成 C2 对称 2,2'-联吡啶-α,α'-1-叔丁基二醇配体


开发了一种有效且实用的方法来合成 C2 对称 2,2'-联吡啶-α,α'-1-叔丁基二醇配体。所公开的合成涉及在NiCl2/Zn/PPh3条件下酮溴吡啶的乌尔曼自偶联，然后使用RuII Noyori-Ikariya催化剂将立体选择性双氢转移至获得的2,2'-联吡啶-二酮。该方法成功合成了 2,2'-联吡啶-α,α'-1-叔丁基二醇，即 (S,S)-Bolm 配体，具有定量产率和优异的立体选择性（ee > 99.5%） ，de > 99.5%），从容易获得的起始材料中总产率为 69%。