Synthesis, <i>cis</i>/<i>trans</i> Isomerization, and Reactivity of Palladium Alkyl Complexes That Contain a Chelating N-Heterocyclic-Carbene Sulfonate Ligand
作者:Xiaoyuan Zhou、Richard F. Jordan
DOI:10.1021/om200482a
日期:2011.9.12
C-O}PdC(═NtBu)Me}(tBuNC) (9), in which the acyl and iminoacyl ligands are cis to the NHC ligand, via stereospecific displacement of Ar-SO3– by the substrate followed by migratory insertion. The bis-isocyanide adduct κ1-C-C-O}PdMe(tBuNC)2, in which the tBuNC ligands are trans, is an intermediate in the formation of 9. tBuNC reversibly displaces the Ar-SO3– ligand of 9 to form κ1-C-C-O}PdC(═NtBu)Me}(tBuNC)2 (10)
钯的烷基配合物掺入NHC-磺酸酯配体的化学Ñ(2,6- -我镨2 -Ph) - ñ '-2-苯磺酸-NHC([CO] -,NHC =环-CNCH 2 CH 2 Ñ )进行了说明。CO}的Ag(反应2)用Pd 2(μ-Cl)的2我2(PPH 3)2次,得到顺式C,C- CO} PDME(PPH 3)(3,79%)。的反应2用Pd 2(μ-Cl)的2我2(2,6-lutidine)2在25°C下的CH 2 Cl 2中给出反式-C,C- CO} PdMe(2,6-lutidine)(4a)和顺式C,C的4/1混合物-CO} PdMe(2,6-lutidine)(4b),通过重结晶分别分离出产率为62%和18%。所述NHC磺酸盐配位体结合在一κ 2 - C,O中的方式3和图4a,b。通过Ar-SO 3的解离,4a异构化为4b –单元形成形状不稳定的三坐标中间物。氢键供体(CD 3 OD,鎓)和路易斯酸(B(C