The versatility of a Bedford-type palladacycle 1, namely [Pd(µ-Cl)κ2-P,C-P(OC6H2-2,4-tBu2)(OC6H3-2,4-tBu2)2}}2], as a primary Pd source, in combination with the ligand bis-1,1′-(diphenylphosphino)ferrocene (dppf) has been established in carbonylation reactions of aryl and heteroaryl bromides with methanol, piperidine and related nucleophiles. Palladacycle 1 has been compared with other primary Pd sources, e.g. (PhCN)2PdCl2 and Pd(OAc)2. The efficacy of the carbonylation processes appear to be linked to the [Pd] concentration, substrate : catalyst ratio, CO pressure and reaction temperature. In amidocarbonylation, double carbonylation is observed for certain organohalides. In the case of 2,5-dibromopyridine, regioselective amination (Hartwig–Buchwald type) also occurs as a side-reaction.
一种Bedford型
钯环化合物1,即[Pd(µ-Cl)κ2-P,C-P(OC6H2-2,4-tBu2)(OC6H3-2,4-tBu2)2}}2],作为主要的
钯源,其多功能性已在与醇、
哌啶及相关亲核试剂的芳基和杂芳基
溴化物的羰基化反应中得到证实。
钯环化合物1已与其他主要的
钯源进行比较,例如(PhCN)2PdCl2和Pd(OAc)2。羰基化过程的有效性似乎与[
钯]浓度、底物与催化剂的比例、
一氧化碳压力和反应温度有关。在胺羰基化过程中,某些有机卤化物观察到了双羰基化现象。在2,5-二
溴吡啶的情况下,还发生了区域选择性
氨基化(Hartwig–Buchwald型)的副反应。