Solvent-less and fluoride-free hiyama reaction of arylsiloxanes with aryl bromides and chlorides promoted by sodium hydroxide:: A useful protocol for palladium recycling and product isolation
Solvent-less and fluoride-free hiyama reaction of arylsiloxanes with aryl bromides and chlorides promoted by sodium hydroxide:: A useful protocol for palladium recycling and product isolation
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DOI：
10.1002/adsc.200505494
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发表时间：
2006-05-01
影响因子：
5.4
通讯作者：
Najera, Carmen
中科院分区：
文献类型：
--
作者：
Alacid, Emilio;Najera, Carmen
钯盐和肟衍生的环钯在低催化剂负载量（0.001-0.1 mol% Pd）、无氟化物条件下催化芳基硅氧烷与芳基溴和芳基氯化物的交叉偶联反应，得到联芳基和杂联芳基。对于一些失活的芳基溴和芳基氯，相应的交叉偶联需要 TBAB 作为添加剂。浓氢氧化钠水溶液（50%）在空气中几乎没有溶剂的情况下促进了这种桧山反应，收率良好。该过程可以在 120 摄氏度下在压力管中加热或在微波辐射下进行。该方案允许钯回收，并通过乙醚萃取促进产品的最终分离。
Palladium salts and oxime-derived palladacycles catalyze the cross-coupling reaction of arylsiloxanes with aryl bromides and chlorides in low catalyst loading (0.001-0.1 mol % of Pd) under fluoride-free conditions to provide biaryls and heterobiaryls. For some deactivated aryl bromides and for aryl chlorides, the corresponding cross-couplings need TBAB as additive. Concentrated aqueous sodium hydroxide (50%) promoted this Hiyama reaction in practically the absence of solvents under air in good yields. The process can be performed at 120 degrees C either under heating in a pressure tube or under microwave irradiation. This protocol allows palladium recycling and facilitates the final isolation of the products simply by ether extraction.