Regioselective functionalization of iminophosphoranes through Pd-mediated C–H bond activation: C–C and C–X bond formation
作者:David Aguilar、Rafael Navarro、Tatiana Soler、Esteban P. Urriolabeitia
DOI:10.1039/c003241g
日期:——
The orthopalladation of iminophosphoranes [R3PNâC10H7-1] (R3 = Ph31, p-Tol32, PhMe23, Ph2Me 4, NâC10H7-1 = 1-naphthyl) has been studied. It occurs regioselectively at the aryl ring bonded to the P atom in 1 and 2, giving endo-[Pd(μ-Cl)(C6H4-(PPh2N-1-C10H7)-2)-κ-C,N]2 (5) or endo-[Pd(μ-Cl)(C6H3-(P(p-Tol)2NâC10H7-1)-2-Me-5)-κ-C,N]2 (6), while in 3 the 1-naphthyl group is metallated instead, giving exo-[Pd(μ-Cl)(C10H6-(NPPhMe2)-8)-κ-C,N]2 (7). In the case of 4, orthopalladation at room temperature affords the kinetic exo isomer [Pd(μ-Cl)(C10H6-(NPPh2Me)-8)-κ-C,N]2 (11exo), while a mixture of 11exo and the thermodynamic endo isomer [Pd(μ-Cl)(C6H4-(PPhMeNâC10H7-1)-2)-κ-C,N]2 (11endo) is obtained in refluxing toluene. The heating in toluene of the acetate bridge dimer [Pd(μ-OAc)(C10H6-(NPPh2Me)-8)-κ-C,N]2 (13exo) promotes the facile transformation of the exo isomer into the endo isomer [Pd(μ-OAc)(C6H4-(PPhMeNâC10H7-1)-2)-κ-C,N]2 (13endo), confirming that the exo isomers are formed under kinetic control. Reactions of the orthometallated complexes have led to functionalized molecules. The stoichiometric reactions of the orthometallated complexes [Pd(μ-Cl)(C10H6-(NPPhMe2)-8)-κ-C,N]2 (7), [Pd(μ-Cl)(C6H4-(PPh2NPh)-2)]2 (17) and [Pd(μ-Cl)(C6H3-(C(O)NPPh3)-2-OMe-4)]2 (18) with I2 or with CO results in the synthesis of the ortho-halogenated compounds [PhMe2PNâC10H6âI-8] (19), [IâC6H4-(PPh2NPh)-2] (21) and [Ph3PNC(O)C6H3âI-2-OMe-5] (23) or the heterocycles [C10H6-(NPPhMe2)-1-(C(O))-8]Cl (20), [C6H5-(NPPh2-C6H4âC(O)-2]ClO4 (22) and [C6H3-(C(O)-1,2-NâPPh3)-OMe-4]Cl (24).
研究了亚氨基正膦 [R3PN→C10H7-1](R3 = Ph31、p-Tol32、PhMe23、Ph2Me 4、N→C10H7-1 = 1-萘基)的邻位钯化。它区域选择性地发生在与 1 和 2 中的 P 原子键合的芳环上,得到内-[Pd(μ-Cl)(C6H4-(PPh2N-1-C10H7)-2)-γ-C,N]2 (5 ) 或者内-[Pd(μ-Cl)(C6H3-(P(p-Tol)2N−C10H7-1)-2-Me-5)-μ-C,N]2 (6),而在 3 中 1 -萘基被金属化,从而得到exo-[Pd(μ-Cl)(C10H6-(NPPhMe2)-8)-μ-C,N]2 (7)。在4的情况下,室温下的正钯化提供了动力学外型异构体[Pd(μ-Cl)(C10H6-(NPPh2Me)-8)-γ-C,N]2 (11exo),而11exo和热力学内异构体在回流甲苯中得到[Pd(μ-Cl)(C6H4-(PPhMeN–C10H7-1)-2)-μ-C,N]2 (11endo)。在甲苯中加热乙酸桥二聚体 [Pd(μ-OAc)(C10H6-(NPPh2Me)-8)-γ-C,N]2 (13exo) 促进外型异构体轻松转化为内型异构体[Pd(μ-OAc)(C6H4-(PPhMeN–C10H7-1)-2)-γ-C,N]2 (13endo),证实外型异构体是在动力学控制下形成的。邻位金属化配合物的反应产生了功能化分子。邻位金属化配合物的化学计量反应 [Pd(μ-Cl)(C10H6-(NPPhMe2)-8)-μ-C,N]2 (7), [Pd(μ-Cl)(C6H4-(PPh2NPh)-2 )]2 (17) 和[Pd(μ-Cl)(C6H3-(C(O)NPPh3)-2-OMe-4)]2 (18) 与 I2 或与 CO 生成邻位卤代化合物 [PhMe2PN–C10H6– [I-8] (19)、[I-C6H4-(PPh2NPh)-2] (21) 和[Ph3PNC(O)C6H3→I-2-OMe-5] (23) 或杂环 [C10H6-(NPPhMe2)-1-(C(O))-8]Cl (20)、[C6H5-(NPPh2) -C6H4→C(O)-2]ClO4 (22) 和[C6H3-(C(O)-1,2-N·PPh3)-OMe-4]Cl (24)。