Palladium-catalyzed or -promoted reductive carbon-carbon coupling. Effects of phosphines and carbon ligands
作者:Ei-ichi Negishi、Tamotsu Takahashi、Kazunari Akiyoshi
DOI:10.1016/0022-328x(87)80048-7
日期:1987.11
The reaction of Cl2Pd(PEt3)2 with 2 equiv of (E)-t-BuCHCHLi, t-BuCCLi, or MeLi gives the corresponding R12Pd(PEt3)2 in a nearly quantitative yield without producing R1R1, where R1 = (E)-t-BuCHCH, t-BuCC, or Me. The reaction of PhLi or PhZnCl gives Ph2Pd(PEt3)2 and biphenyl in approximately 90 and 10% yields, respectively. On the other hand, the corresponding reaction of Cl2Pd(PPh3)2 produces R1R1
Cl 2 Pd(PEt 3)2与2当量的(E)-t-BuCH = CHLi,t-BuC = CLi或MeLi的反应以几乎定量的产率得到相应的R 1 2 Pd(PEt 3)2而不产生R 1 R 1,其中R 1 =(E)-t-BuCH = CH,t-BuC = C或Me。PhLi或PhZnCl的反应分别以大约90%和10%的收率得到Ph 2 Pd(PEt 3)2和联苯。另一方面,Cl 2 Pd(PPh 3)2的相应反应在每种情况下,在1小时内产生的R 1 R 1的产率均> 95%。尝试检测R 1 2 Pd(PPh 3)2的尝试失败。从使用PEt 3,PPhMe 2和PPh 2 Me的情况可以推断出它们形成为不稳定的中间体。R 1 R 1的形成容易度与PR 3的碱度成反比,即,PEt 3<PPhMe 2<PPh 2 Me <PPh 3。尽管我2 Pd(PEt 3)2是顺式,在本研究中制备的所有其他R