In Situ Generation of ArCu from CuF<sub>2</sub>
Makes Coupling of Bulky Aryl Silanes Feasible and Highly Efficient
作者:Juan delPozo、Juan A. Casares、Pablo Espinet
DOI:10.1002/chem.201504435
日期:2016.3.14
fairly hindered aryl silanes with aryl, anisyl, phenylaldehyde, p‐cyanophenyl, p‐nitrophenyl, or pyridyl iodides of conventional size. The reaction involves the activation of the silane by CuII, followed by disproportionation and transmetalation from the CuI(aryl) to PdII, upon which coupling takes place. CuIII formed during disproportionation is reduced to CuI(aryl) by excess aryl silane, so that
Pd / CuF 2的双金属体系(在Pd中催化而在Cu中以化学计量)非常有效且具有选择性,可将相当受阻的芳基硅烷与传统的芳基,茴香基,苯甲醛,对氰基苯基,对硝基苯基或吡啶基碘化物偶联尺寸。该反应包括通过Cu II活化硅烷,然后发生歧化和从Cu I(芳基)到Pd II的重金属转移,然后发生偶联。歧化过程中形成的Cu III被过量的芳基硅烷还原为Cu I(芳基),因此CuF 2体系被完全转化为Cu I(芳基)并用于偶联。此外,不需要额外的氟化物源。在受阻芳基硅烷的竞争反应中发现了对偶联的有趣的尺寸选择性。到目前为止,易于获得的[PdCl 2(IDM)(AsPh 3)](IDM = 1,3-二甲基咪唑-2-亚烷基)是最好的催化剂,分离出的产物基本上不含As或Pd(<1 ppm)。该过程的机械方面已通过实验检查和讨论。