Aryl group interchange between triarylphosphines catalyzed by Group VIII transition metals

Abstract

CH3CN)2MoBr(CO)2(7)3-C8H13)], 81923-03-7; (+)-[NMCpMo-(NO)(CO)(i/3-C8H13)]BF4, 89689-90-7; (+)-[NMCpMo(NO)-(CO)(i73-C8H13)]PF6, 89772-14-5; (-)-[NMCpMo(NO)(CO)(7,3-C8H13)]BF4, 89771-47-1; (+)-NMCpMo(NO)(Br)(7,3-C8H13), 89689-91-8; (-)-NMCpMo(NO)(Br)(r)3-C8H13), 89771-48-2; (-)D-NMCpMo(NO) (CO) (7j2-C8H13OH), 89689-92-9; (-)D-NMCpMo-(NO)(CO)(tj2-C8H13D), 89689-93-0; Mo(CO)6,13939-06-5; NOBF4, 14635-75-7; NaBr, 7647-15-6; 3-bromocyclooctene, 7422-06-2;(-)-cycloocten-3-ol, 62210-83-7; (-)-3-deuteriocyclooctene, 89689-94-1; silver hexafluorophosphate, 26042-63-7; neomenthylcyclopentadiene, 89689-88-3. Supplementary Material Available: Tables of anisotropic temperature factors, calculated hydrogen atom positions, and structure factors for both crystal modifications of the bromide structure and tables of crystal data, positional parameters, bond lengths, and bond angles for the P2i modification (26 pages). Ordering information is given on any current masthead page.

Transition metal-mediated metathesis between P–C and M–C bonds: Beyond a side reaction

“…Actually, literature precedent has often shown the reversible nature of this P-C bond cleavage and forming. As mentioned above, in 1984, two independent works reported that a P-C/P-C cross-metathesis reaction is a reversible process which seems to proceed through oxidative addition and consecutive reductive elimination by Pd(0) in both cases [34][35]. Inspired by these works, Morandi and coworkers systematically studied both the forward and the reverse reaction of a range of meta-and para-substituted triarylphosphines with PPh3 using both catalytic amount of Pd(0) and PhI.…”

“…In 1984, Bryant et al discovered the intermolecular aryl scrambling of triarylphosphines when using several transition metals (e.g. Rh, Co, Os, Ni, Pd, and Ru) as catalysts with two different kinds of triarylphosphines (Scheme 4) [34]. The reaction mixture has shown complete equilibration between reactants and products.…”

“…As shown from the previous examples, two pathways can be envisioned for the P-C bond metathesis. A first possibility is the direct oxidative addition of neutral P-C bonds followed by transmetallation (Scheme 5) [34][35]50]. A second option proceeds through initial reductive elimination of an M-Ar species with a coordinated phosphine ligand to generate a phosphonium intermediate that can subsequently undergo oxidative addition to form a new M-Ar bond and a new phosphine product (Scheme 8) [28][29][30][31].…”

“…Additionally, a mechanism involving initial oxidative addition of neutral P-C bond was also proposed on the basis of their observation that the desired cyclized product was obtained from Pd(BINAP)2 complex in good yield (Scheme 59, bottom). The fact that Pd(PPh3)4 exhibited significant catalytic activity (49% yield vs. 93% yield when applied [(allyl)PdCl]2) indicates that the latter mechanism cannot be excluded [34][35]. Interestingly, the authors reported the cyclization of binaphthyl-type bisphosphines that cannot be accessed through previously reported methods from binaphthyl monophosphine (71) and (pseudo)halide substituted binaphthyl monophosphine (72), respectively (Scheme 58) [124][125].…”

Synthetic Applications of Transition‐Metal‐Catalyzed C−P Bond Cleavage

“…To develop more efficient catalytic reactions, the fundamental behavior of triarylphosphine in the presence of a transition‐metal catalyst must be understood. Abatjoglou and Bryant studied Group VIII transition‐metal‐catalyzed C aryl −P bond metathesis (Scheme ) . Different from aforementioned partial utilization of phosphine through C−P bond activation, their findings suggested that both the cleaved aryl moiety and phosphino moiety could be used as building blocks at the same time.…”