Synthesis of 2,4,6-trimethylphenylcalcium iodide and degradation in THF solution
Synthesis of 2,4,6-trimethylphenylcalcium iodide and degradation in THF solution
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DOI：
10.1002/anie.200503452
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发表时间：
2006-01-01
影响因子：
16.6
通讯作者：
Westerhausen, M
中科院分区：
文献类型：
--
作者：
Fischer, R;Gärtner, M;Westerhausen, M
与100多年前由Grignard通过直接合成制备的烷基和芳基卤化镁相比，重碱土金属的有机金属化学很少受到关注。[1]其主要原因是制备困难和所得有机金属化合物的高反应性。一方面，钙、锶和钡金属的反应性不是很强，必须在使用前活化。另一方面，有机金属衍生物倾向于裂解醚。此外，由于高度离子化的金属-碳键，这些化合物通常不溶于普通有机溶剂。为了克服这些问题，已经开发了几种制备方法。[1，2]有机钙化合物的主要获取途径是：1）卤代烃与钙蒸气的反应（共缩合反应），[3，4] 2）钙插入到溶液中的碳-卤键中（直接合成），[5] 3）用钙取代电正性较弱的金属（金属转移），[6，7]4）通过钙或钙化合物使H-酸性烃去质子化（金属化），[8] 5）有机钾化合物与无水CaI 2的反应（复分解反应）。[9，10]贝克曼在1905年描述了苯基碘化钙的合成;他应用了在乙醚中的直接合成，并用微量碘活化碱土金属。[11]80多年后，Bickelhaupt及其同事报道了在208 ℃下在THF中合成二苯基钙。[12]然而，既没有提供产量，也没有提供物理数据。这些苯基钙化合物通过衍生化进行表征和鉴定，例如，通过水解或与醛、酮、酯、乙烯基炔或氯锡烷反应，然后进行水解后处理程序。
In contrast to the alkyl-and arylmagnesium halides prepared by Grignard by direct synthesis more than a hundred years ago, the organometallic chemistry of the heavier alkalineearth metals has received little attention.[1] The main reasons for this are the difficult preparation and the high reactivity of the resulting organometallic compounds. On the one hand, calcium, strontium, and barium metals are not very reactive and must be activated prior to use. On the other hand, the organometallic derivatives tend to cleave ether. Furthermore, owing to the highly ionic metal–carbon bonds these compounds often are insoluble in common organic solvents. In order to overcome these problems several preparative procedures have been developed.[1, 2] The main access routes to organocalcium compounds are: 1) the reaction of halogenated hydrocarbons with calcium vapor (cocondensation reaction),[3, 4] 2) the insertion of calcium into a carbon–halogen bond in solution (direct synthesis),[5] 3) the substitution of a less electropositive metal by calcium (transmetalation),[6, 7]4) the deprotonation of H-acidic hydrocarbons by calcium or calcium compounds (metalation),[8] 5) the reaction of a organopotassium compound with anhydrous CaI2 (metathesis reaction).[9, 10]Beckmann described the synthesis of phenylcalcium iodide in 1905; he applied the direct synthesis in diethyl ether and activated the alkaline-earth metal with a trace of iodine.[11] More than 80 years later the synthesis of diphenylcalcium in THF at À208C was reported by Bickelhaupt and co-workers.[12] However, neither yields nor physical data were presented. These phenylcalcium compounds were characterized and identified by derivatization, for example, by hydrolysis or reactions with aldehydes, ketones, esters, vinylalkynes, or chlorostannanes followed by hydrolytic workup procedures.