A highly active palladium catalyst for intermolecular hydroamination. Factors that control reactivity and additions of functionalized anilines to dienes and vinylarenes
A highly active palladium catalyst for intermolecular hydroamination. Factors that control reactivity and additions of functionalized anilines to dienes and vinylarenes
复制标题
DOI：
10.1021/ja056003z
复制
发表时间：
2006-02-15
影响因子：
15
通讯作者：
Hartwig, JF
中科院分区：
文献类型：
--
作者：
Johns, AM;Utsunomiya, M;Hartwig, JF
我们报道了一种用于乙烯分子间氢胺化反应的催化剂，该催化剂比以前发表的催化剂对这一过程的活性要高得多。有了这种更具活性的催化剂，我们证明了胺与乙烯和二烯的加成反应是在潜在的活性官能团存在的情况下发生的，例如带有可烯化氢的酮、游离醇、游离羧酸、游离酰胺、腈和酯。这些反应的催化剂是由(Pd(eta(3)-烯丙基)氯(添加或不添加AgOTf)或[Pd(CH3CN)(4)](BF4)与Xantphos(9，9-dimethyl-4，5-bis(diphenylphosphino)xanthene)，生成的具有大P-Pd-P咬合角的络合物。研究了胺对ETA(3)-苯乙基和ETA(3)-烯丙基络合物的C-N键形成速率，以确定咬合角对这种亲核攻击速率的影响。对含有不同双膦配体的模型ETA(3)-苄基配合物的研究表明，P-Pd-P咬合角较大的配合物的亲核攻击速度较快。对取代的不对称和未被取代的对称模型ETA(3)-烯丙基配合物的研究表明，对Xantphos连接的配合物的亲核攻击比对含小咬合角配体的配合物的亲核攻击快，对大咬合角配体的不对称烯丙基配合物的亲核攻击比对小咬合角配体的不对称烯丙基配合物的亲核攻击快。然而，用P-31核磁共振波谱监测双烯的催化反应表明，活性催化剂的浓度是控制小咬角膦配合物催化对称双烯反应速率的主要因素。反离子的同一性也影响了反应的速度：烯丙基钯配合物与氯离子的反应比烯丙基钯配合物与三氟酸盐或四氟硼酸盐反离子的反应更快。正如人们经常观察到的，烯丙基和苄基络合物的动力学也取决于反离子的同一性。
We report a catalyst for intermolecular hydroamination of vinylarenes that is substantially more active for this process than catalysts published previously. With this more reactive catalyst, we demonstrate that additions of amines to vinylarenes and dienes occur in the presence of potentially reactive functional groups, such as ketones with enolizable hydrogens, free alcohols, free carboxylic acids, free amides, nitriles, and esters. The catalyst for these reactions is generated from (Pd(eta(3)-allyl)Cl (with or without added AgOTf) or [Pd(CH3CN)(4)](BF4) and Xantphos (9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene), which generates complexes with large P-Pd-P bite angles. Studies on the rate of the C-N bond-forming step that occurs by attack of amine on an eta(3)-phenethyl and an eta(3)-allyl complex were conducted to determine the effect of the bite angle on the rate of this nucleophilic attack. Studies on model eta(3)-benzyl complexes containing various bisphosphines showed that the nucleophilic attack was faster for complexes containing larger P-Pd-P bite angles. Studies of substituted unsymmetrical and unsubstituted symmetrical model eta(3)-allyl complexes showed that nucleophilic attack on complexes ligated by Xantphos was faster than on complexes bearing ligands with smaller bite angles and that nucleophilic attack on unsymmetrical allyl complexes with larger bite angle ligands was faster than on unsymmetrical allyl complexes with smaller bite angle ligands. However, monitoring of catalytic reactions of dienes by P-31 NMR spectroscopy showed that the concentration of active catalyst was the major factor that controlled rates for reactions of symmetrical dienes catalyzed by complexes of phosphines with smaller bite angles. The identity of the counterion also affected the rate of attack: reactions of allylpalladium complexes with chloride counterion occurred faster than reactions of allylpalladium complexes with triflate or tetrafluoroborate counterion. As is often observed, the dynamics of the allyl and benzyl complexes also depended on the identity of the counterion.