Organozinc reagents are versatile building blocks for introducing C(sp²)-C(sp³) and C(sp³)-C(sp³) bonds into organic structures. However, despite their ample synthetic versatility and broad functional group tolerance, the use of organozinc reagents in the laboratory is limited because of their instability, exothermicity and water sensitivity, as well as their labor-intensive preparation. Herein, we describe an on-demand synthesis of these useful reagents under continuous flow conditions, overcoming these primary limitations and supporting widespread adoption of these reagents in synthetic organic chemistry. To exemplify this procedure, a solution of ethyl zincbromoacetate is prepared by flowing ethyl bromoacetate through a column containing metallic zinc. The temperature of the column is controlled by a heating jacket and a thermocouple in close contact with it. Advice on how to perform the procedure using alternative equipment is also given to allow a wider access to the methodology. Here we describe the preparation of 50 ml of solution, which takes 1 h 40 min, although up to 250-300 ml can be prepared with the same column setup at a rate of 30 ml per h. The procedure provides the reagent as a clean solution with reproducible concentration. Organozinc solutions generated in flow can be coupled to a second flow reactor to perform a Reformatsky reaction or can be collected over a flask containing the required reagents for a batch Negishi reaction.

中文翻译：

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在连续流动条件下按需合成有机卤化锌。

有机锌试剂是用于引入C（sp ²）-C（sp ³）和C（sp ³）-C（sp ³）的通用构建基块）结合成有机结构。然而，尽管有机锌试剂具有足够的合成多功能性和广泛的官能团耐受性，但由于它们的不稳定性，放热性和水敏感性以及劳动强度大的制备，在实验室中的使用受到限制。在本文中，我们描述了在连续流动条件下按需合成这些有用的试剂，克服了这些主要限制并支持了这些试剂在合成有机化学中的广泛采用。为了举例说明该程序，通过使溴乙酸乙酯移过含有金属锌的柱子来制备溴乙酸锌乙酯的溶液。色谱柱的温度由加热套和与之紧密接触的热电偶控制。还提供了有关如何使用替代设备执行该程序的建议，以使您可以更广泛地使用该方法。在这里我们描述了50 ml溶液的制备，这需要1 h 40分钟，尽管使用相同的色谱柱设置可以以每小时30 ml的速率制备多达250-300 ml的溶液。该程序提供浓度可重现的清洁溶液试剂。流动产生的有机锌溶液可以连接到第二个流动反应器以进行Reformatsky反应，也可以收集在装有用于批量Negishi反应所需试剂的烧瓶中。该程序提供浓度可重现的清洁溶液试剂。流动产生的有机锌溶液可以连接到第二个流动反应器以进行Reformatsky反应，也可以收集在装有用于批量Negishi反应所需试剂的烧瓶中。该程序提供浓度可重现的清洁溶液试剂。流动产生的有机锌溶液可以连接到第二个流动反应器以进行Reformatsky反应，也可以收集在装有用于批量Negishi反应所需试剂的烧瓶中。