Internal borylation occurs upon activation of aryl di-isopropylphosphinite boranes with HNTf2 to give heterocyclic intermediates that can be reductively quenched to afford 6 or treated with KHF2 to give the phenolic potassium aryl trifluoroborate salts 10. The latter salts are useful for Pd-catalyzed coupling with aryl iodides under Molander conditions, provided that precautions are taken to remove the KNTf2 byproduct from the preceding KHF2 step.
Ortho Derivatization of Phenols through C–H Nickelation: Synthesis, Characterization, and Reactivities of Ortho-Nickelated Phosphinite Complexes
作者:Boris Vabre、Félix Deschamps、Davit Zargarian
DOI:10.1021/om500938u
日期:2014.11.24
excess ligand (4a → 3a) or excess Ni precursor (3a → 4a). Treatment of 3a or 4a with benzylbromide at 90 °C over extended periods led to benzylation of the Ni–aryl moiety in these complexes. Examination of the cyclometalation pathway for i-Pr2POPh has shown that the first species formed from its ambient-temperature reaction with [(i-PrCN)NiBr2]n is trans-(i-Pr2POPh)2NiBr2 (2a). NMR studies showed that 2a
Catalysis of Kumada–Tamao–Corriu coupling by a (POCOP)Rh pincer complex
作者:Samuel D. Timpa、Claudia M. Fafard、David E. Herbert、Oleg V. Ozerov
DOI:10.1039/c1dt10161g
日期:——
A pincer-based (POCOP)Rh catalyst is demonstrated to be an active and well-defined catalyst for the coupling of select aryl and alkyl Grignards with aryl iodides. The proposed intermediacy of oxidative addition of aryl halides to (POCOP)RhI is supported by the isolation of the oxidative addition product.
事实证明,基于钳子的(P O C O P)Rh催化剂是一种活性良好的催化剂,可用于将精选的芳基和烷基格氏试剂与碘代芳烃偶联。分离出的氧化加成产物支持了将芳基卤化物氧化加成(P O C O P)Rh I的中间方法。
C–H Nickelation of Aryl Phosphinites: Mechanistic Aspects
作者:Loïc P. Mangin、Davit Zargarian
DOI:10.1021/acs.organomet.8b00899
日期:2019.4.8
studies have shown that nickelation is faster with aryl phosphinites bearing electron-donating substituents (Hammett slope ρ ≈ −4) and the proton transfer is rate limiting (KIE ≈ 11). The activation parameters were found to be ΔH⧧ = 17.7 kcal mol–1 and ΔS⧧ = −27.1 cal mol–1 K–1. DFT analyses have provided support for these findings and suggest that aryl phosphinite C–H nickelation proceeds via an ion-pair-assisted
Some phosphinite complexes of Rh and Ir, their intramolecular reactivity and DFT calculations about their application in biphenyl metathesis
作者:Klaus Ruhland、Peter Gigler、Eberhardt Herdtweck
DOI:10.1016/j.jorganchem.2007.09.035
日期:2008.3
catalytic cycle for biphenyl metathesis containing the coupling of oxidative addition and reductive elimination of the bridging C–C single bond in the biphenyl fragment using RhI/III complexes and the concept of chelating assistance was calculated using DFT (B3PW91/LANL2DZ). According to the calculations the activation energy of the oxidative addition is about 30 kcal/mol and for the reductive elimination
使Biphen(OPR 2)(具有R:Ph,iPr,Cy)与[Rh(COE)2 Cl] 2反应。接收到相应的μ-氯桥联的二聚体。包括[Biphen(OPCy 2)RhCl] 2的X射线分析。该化合物在溶液中显示出动态行为,归因于单体/二聚体平衡。显示了Biphen配体与Milsteins PCP钳型配体的差异。联苯复分解的催化循环,包括使用Rh I / III联苯片段中桥连式C–C单键的氧化加成和还原消除配合物和螯合辅助的概念是使用DFT(B3PW91 / LANL2DZ)计算的。根据计算,氧化加成的活化能为约30kcal / mol,而还原消除的活化能为约19kcal / mol。迄今为止,fac–Rh III配合物是最稳定的化合物,但在动力学上不利于其形成。通过将次膦酸盐与金属进行预配位(包括四个此类化合物的X射线结构),然后用2当量处理,可以合成预催化剂(COD)M(Ph- O -PR
Single Oxygen-Atom Insertion into PB Bonds: On- and Off-Metal Transformation of a Borylphosphine into a Borylphosphinite
作者:Jonathan A. Bailey、Hazel A. Sparkes、Paul G. Pringle
DOI:10.1002/chem.201500378
日期:2015.3.27
An oxygen atom is selectively inserted into the PB bond of a borylphosphine (L1) by reaction with Me3NO to afford the corresponding borylphosphinite (L2). This transformation can also be effected when L1 is coordinated to rhodium. The ν(CO) values for trans‐[RhCl(CO)(L)2] reveal very different electronic properties for coordinated L1 and L2 which translate into the strikingly different performances