the overall computed barrier is 16.8 kcal mol−1. This new mechanism is consistent with all of the experimental data relating to substituent effects on relative reaction rates and branched/linear selectivities, including new results on the methoxycarbonylation of phenylacetylene using (4-Me2N-Py)PPh2 and (6-Cl-Py)PPh2 ligands. This ligand is found to decrease catalytic activity over PyPPh2, thus invalidating
经修订的原位炔烷氧羰基的基机构通过与hemilabile P上的Pd催化剂,N
配体(PyPPh 2,PY = 2-
吡啶基)已被充分表征在密度泛函理论的B3PW91-D3 / PCM电平。这条路线的关键中间体是
丙烯酰基和η 3 -
丙烯-1-酰基配合物容易进行
甲醇。使用两个半不稳定的P,N
配体并且其中一个或两个都质子化,计算得出的总势垒为16.8 kcal mol -1。这一新机理与所有有关取代基对相对反应速率和支链/线性选择性的影响的实验数据一致,包括使用(4-Me 2N-Py)PPh 2和(6-Cl-Py)PPh 2
配体。发现该
配体降低了对PyPPh 2的催化活性,从而使先前表征的原位基础机理无效。