A range of stable ytterbium(II) amino ether-phenolato amido complexes of the type {LONxOy}Yb{N(SiMe3)(2)}, together with a congeneric samarium(II) and two calcium and strontium amido and alkyl derivatives, have been synthesized. They constitute very active, fully regioselective (anti-Markovnikov), and chemoselective precatalysts for the intermolecular hydrophosphination of styrene derivatives with PhPH2, achieving TONs up to 2150, TOFs up to 30 h(-1) and chemoselectivities in the region of 95-99%. The ytterbium(II) precatalysts, among which is most prominently {LONO4}Yb{N(SiMe3)(2)} (3), where the ligand possesses a 15-c-5-aza-crown ether side arm, outperform their related calcium analogues, and the activity of the catalyst increases substantially with the denticity of the ligand. The rate law rate = k[p-Bu-t-styrene] [3] was established, following kinetic monitoring of the hydrophosphination of p-Bu-t-styrene and PhPH2 catalyzed by 3. The kinetic studies also revealed that the reactions are entropically driven and that reaction rates increase when electron-withdrawing groups are introduced at the Para position of the styrenic substrate. It is proposed that these catalyzed hydrophosphination reactions proceed by rate-limiting olefin insertion into the [Yb] phosphide bond. The chemoselective one-pot, two-step double hydrophosphination of PhPH2 with 2 equiv of styrene yields tertiary phosphines. It obeys an unusual kinetic profile where formation of the tertiary phosphine starts only when complete consumption of PhPH2 is first ensured. This sequence was used to obtain asymmetric tertiary phosphines with excellent selectivity.
Barium complexes with crown-ether-functionalised amidinate and iminoanilide ligands for the hydrophosphination of vinylarenes
作者:Erwann Le Coz、Hanieh Roueindeji、Thierry Roisnel、Vincent Dorcet、Jean-François Carpentier、Yann Sarazin
DOI:10.1039/c9dt01512d
日期:——
The detailed multistep syntheses of two nitrogen-based sterically congested iminoanilidine and amidine proligands bearing a tethered 15-member aza-ether-crown macrocycle, namely I^Acrown}H and Amcrown}H, are reported. These proligands react with [BaN(SiMe2H)2}2·(thf)n] to generate the heteroleptic barium complexes [I^Acrown}BaN(SiMe2H)2] (5) and [Amcrown}BaN(SiMe2H)2] (6) in high yields. These
Ln(<scp>ii</scp>) amido complexes coordinated by ring-expanded N-heterocyclic carbenes – promising catalysts for olefin hydrophosphination
作者:Ivan V. Lapshin、Anton V. Cherkasov、Andrey F. Asachenko、Alexander A. Trifonov
DOI:10.1039/d0cc05424k
日期:——
First Ln(II) ring-expanded NHC complexes (er-NHC)Ln[N(SiMe3)2]2 (Ln = Sm, Yb) are synthesized and proved to be highly efficient pre-catalysts for the intermolecular hydrophosphination of such indolent substrates as 1-alkenes, cyclohexene and norbornene.
Highly Active, Chemo- and Regioselective Yb<sup>II</sup>and Sm<sup>II</sup>Catalysts for the Hydrophosphination of Styrene with Phenylphosphine
作者:Ivan V. Basalov、Vincent Dorcet、Georgy K. Fukin、Jean-François Carpentier、Yann Sarazin、Alexander A. Trifonov
DOI:10.1002/chem.201500380
日期:2015.4.13
aminoether–phenolate ligands and devoid of coordinated solvent have been structurally characterized. They afford highlyactive, chemoselective and, in the case of monoadditions, 100 % anti‐Markovnikov regiospecific catalysts (down to 0.04 mol % loading) for the hydrophosphination of styrene with PhPH2 under mild conditions.
A bench-stable copper photocatalyst for the rapid hydrophosphination of activated and unactivated alkenes
作者:Steven G. Dannenberg、Rory Waterman
DOI:10.1039/d0cc06570f
日期:——
that have never before been reported with an air-stable catalyst or at ambient temperature. The commercial availability, ease of use, and broad substrate scope of compound 1 make hydrophosphination more available to syntheticchemists.
A Study of Two Highly Active, Air-Stable Iron(III)-μ-Oxo Precatalysts: Synthetic Scope of Hydrophosphination using Phenyl- and Diphenylphosphine
作者:Kimberley J. Gallagher、Maialen Espinal-Viguri、Mary F. Mahon、Ruth L. Webster
DOI:10.1002/adsc.201501179
日期:2016.7.28
The importance of phosphines in synthetic chemistry cannot be underestimated. Catalytic hydrophosphination offers an ideal method to prepare P−C bonds without the need for harsh reaction conditions or stoichiometric amounts of waste by‐product. We herein report our studies into two biocompatible iron(III) complexes in hydrophosphination chemistry using diphenylphosphine under mild and benign reaction