Carbon−Sulfur Bond-Forming Reductive Elimination Involving sp-, sp<sup>2</sup>-, and sp<sup>3</sup>-Hybridized Carbon. Mechanism, Steric Effects, and Electronic Effects on Sulfide Formation
作者:Grace Mann、David Baranano、John F. Hartwig、Arnold L. Rheingold、Ilia A. Guzei
DOI:10.1021/ja981428p
日期:1998.9.1
alkynyl sulfides. Reductive eliminations forming alkenyl alkyl sulfides and aryl alkyl sulfides were the fastest. Eliminations of alkynyl alkyl sulfides were slower, and elimination of dialkyl sulfide was the slowest. Thus the relative rates for sulfide elimination as a function of the hybridization of the palladium-bound carbon follow the trend sp2 > sp ≫ sp3. Rates of reductive elimination were faster
钯硫合络合物 [(L)Pd(R)(SR')],其中 L 是螯合配体,例如 DPPE、DPPP、DPPBz、DPPF 或 TRANSPHOS,R 是甲基、烯基、芳基或炔基配体, R'是芳基或烷基,通过取代或质子转移反应合成。发现所有这些硫醇盐配合物都以高产率进行碳硫键形成还原消除,以形成二烷基硫化物、二芳基硫化物、烷基芳基硫化物、烷基烯基硫化物和烷基炔基硫化物。形成烯基烷基硫化物和芳基烷基硫化物的还原消除是最快的。炔基烷基硫化物的消除较慢,二烷基硫化物的消除最慢。因此,作为钯结合碳杂化函数的硫化物消除的相对速率遵循趋势 sp2 > sp ≫ sp3。对于具有较大咬合角的顺式螯合膦配体,还原消除速率更快。动力学研究,以及自由基捕获的结果……