Nova Ainara, Ujaque Gregori, Maseras Feliu, Lledós Agustí, Espinet Pablo
Departament de Química, Universitat Autonoma de Barcelona, Edifici Cn.- 08193-Bellaterra (Barcelona), Catalonia, Spain.
J Am Chem Soc. 2006 Nov 15;128(45):14571-8. doi: 10.1021/ja0635736.
The transmetalation step of the Stille cross-coupling reaction catalyzed by PdL(2) (L = PH(3), AsH(3)) has been analyzed by means of DFT methods for PhBr as the electrophile and CH(2)=CHSnMe(3) as the nucleophile. Both experimentally proposed mechanisms (cyclic and open) were theoretically studied. For the case of the cyclic mechanism, the associative and dissociative ligand substitution alternatives were both analyzed. For the case of the open mechanism, the cis and the trans pathways were evaluated. All the reaction pathways were also studied taking into account the solvent effects by means of continuum models, for THF and PhCl as solvents. In selected cases, explicit solvent molecules were introduced to account for their potential role as ligands. Theoretical analysis indicates that the open reaction mechanism is preferred for organotriflate systems, whereas the cyclic mechanism is favored for the reaction with organohalide systems.
通过密度泛函理论（DFT）方法，以溴苯作为亲电试剂、乙烯基三甲基锡作为亲核试剂，对由PdL₂（L = PH₃、AsH₃）催化的Stille交叉偶联反应的转金属化步骤进行了分析。对实验提出的两种机制（环状和开链）都进行了理论研究。对于环状机制的情况，对缔合和离解配体取代两种方式都进行了分析。对于开链机制的情况，评估了顺式和反式途径。还通过连续介质模型考虑溶剂效应，以四氢呋喃和氯苯作为溶剂，研究了所有反应途径。在选定的情况下，引入了明确的溶剂分子以考虑它们作为配体的潜在作用。理论分析表明，对于有机三氟甲磺酸酯体系，开链反应机制更有利，而对于与有机卤化物体系的反应，环状机制更受青睐。
