Arylcalcium Iodides in Tetrahydropyran: Solution Stability in Comparison to Aryllithium Reagents
Arylcalcium Iodides in Tetrahydropyran: Solution Stability in Comparison to Aryllithium Reagents
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四氢吡喃中的芳基碘化钙：与芳基锂试剂相比溶液稳定性
DOI：
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发表时间：
2012
期刊：
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通讯作者：
M. Westerhausen
中科院分区：
文献类型：
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作者：
J. Langer;M. Köhler;R. Fischer;F. Dündar;H. Görls;M. Westerhausen
用细分散的钙粉还原四氢吡喃（THP）中的对取代碘苯，得到[(THP)4Ca(C6H4-4-R)I]型芳基碘化钙，R = CH3(1)、Cl(2)、Br(3)、I(4)、OCH3(5)。没有观察到钙在二卤苯中的2倍插入。β-萘基碘化钙[(THP)4Ca(β-Naph)I](6)也可在THP中直接合成。研究了THP中芳基钙化合物的耐久性，并与THF中的耐久性进行了比较，发现THP在室温下的寿命略有提高。此外，还研究了1及其对应物锂[{(THP)2Li}2(μ-Tol)(μ-Br)](7)在THP和THF中的相对反应活性和选择性。α-金属化和随后的环还原是两种情况下观察到的THF的主要途径。在7诱导的降解反应中，鉴定出了碳石化和β-金属化反应产生的几种副产物，而发现1具有更强的选择性。相关的[…]
Reduction of para-substituted iodobenzene in tetrahydropyran (THP) with finely dispersed calcium powder yields arylcalcium iodides of the type [(THP)4Ca(C6H4-4-R)I] with R = CH3 (1), Cl (2), Br (3), I (4), OCH3 (5). A 2-fold insertion of calcium into dihalobenzenes was not observed. The β-naphthylcalcium iodide [(THP)4Ca(β-Naph)I] (6) is also accessible by direct synthesis in THP. The durability of arylcalcium compounds in THP was studied in comparison to that in THF, and a slightly enhanced lifetime in THP at ambient temperature was observed. Furthermore, the relative reactivity and selectivity of 1 and its lithium counterpart [{(THP)2Li}2(μ-Tol)(μ-Br)] (7) in the reaction with THP and THF were studied. α-Metalation and subsequent cycloreversion was the major pathway observed for THF in both cases. In the degradation reaction induced by 7, several byproducts arising from carbolithiation and, surprisingly, from β-metalation reactions were identified, while 1 was found to be more selective. The related [(T...