6372-43-6Relevant academic research and scientific papers
Reduction of tertiary phosphine oxides to phosphine-boranes using Ti(Oi-Pr)4/BH3-THF
Sowa, Sylwia,Pietrusiewicz, K. Micha?
supporting information, (2021/03/17)
A new method for reduction of tertiary phosphine oxides leading to the formation of tertiary phosphine-boranes has been developed. The BH3-THF/Ti(Oi-Pr)4 reducing system enables conversion of triaryl, diarylalkyl and trialkylphosphine oxides directly to their borane analogues in good to high yields. In contrast to the previously reported protocols, the presence of activating groups in the structure of starting material is not necessary for the reaction to occur. The reaction is highly stereoselective and proceeds with predominant retention of configuration at the phosphorus atom. A plausible mechanism of reduction of the P[dbnd]O bond by BH3-THF/Ti(Oi-Pr)4 has been proposed.
Contrasting Synergistic Heterobimetallic (Na–Mg) and Homometallic (Na or Mg) Bases in Metallation Reactions of Dialkylphenylphosphines and Dialkylanilines: Lateral versus Ring Selectivities
Stevens, Michael A.,Hashim, Fairuz H.,Gwee, Eunice S. H.,Izgorodina, Ekaterina I.,Mulvey, Robert E.,Blair, Victoria L.
, p. 15669 - 15677 (2018/09/27)
A series of dialkylphenylphosphines and their analogous aniline substrates have been metallated with the synergistic mixed-metal base [(TMEDA)Na(TMP)(CH2SiMe3)Mg(TMP)] 1. Different metallation regioselectivities for the substrates were observed, with predominately lateral or meta-magnesiated products isolated from solution. Three novel heterobimetallic complexes [(TMEDA)Na(TMP)(CH2PCH3Ph)Mg(TMP)] 2, [(TMEDA)Na(TMP)(m-C6H4PiPr2)Mg(TMP)] 3 and [(TMEDA)Na(TMP)(m-C6H4NEt2)Mg(TMP)] 4 and two homometallic complexes [{(TMEDA)Na(EtNC6H5)}2] 5 and [(TMEDA)Na2(TMP)(C6H5PEt)]2 6 derived from homometallic metallation have been crystallographically characterised. Complex 6 is an unprecedented sodium-amide, sodium-phosphide hybrid with a rare (NaNNaP)2 ladder motif. These products reveal contrasting heterobimetallic deprotonation with homometallic induced ethene elimination reactivity. Solution studies of metallation mixtures and electrophilic iodine quenching reactions confirmed the metallation sites. In an attempt to rationalise the regioselectivity of the magnesiation reactions the C?H acidities of the six substrates were determined in THF solution using DFT calculations employing the M06-2X functional and cc-pVTZ Dunning's basis set.
Heterolytic H2 cleavage and catalytic hydrogenation by an iron metallaboratrane
Fong, Henry,Moret, Marc-Etienne,Lee, Yunho,Peters, Jonas C.
, p. 3053 - 3062 (2013/07/05)
Reversible, heterolytic addition of H2 across an iron-boron bond in a ferraboratrane with formal hydride transfer to the boron gives iron-borohydrido-hydride complexes. These compounds catalyze the hydrogenation of alkenes and alkynes to the respective alkanes. Notably, the boron is capable of acting as a shuttle for hydride transfer to substrates. The results are interesting in the context of heterolytic substrate addition across metal-boron bonds in metallaboratranes and related systems, as well as metal-ligand bifunctional catalysis.
Efficient catalytic hydrogenation of levulinic acid: A key step in biomass conversion
Tukacs, Jozsef M.,Kiraly, David,Stradi, Andrea,Novodarszki, Gyula,Eke, Zsuzsanna,Dibo, Gabor,Kegl, Tamas,Mika, Laszlo T.
supporting information; experimental part, p. 2057 - 2065 (2012/08/14)
γ-Valerolactone (GVL) has been proposed as a sustainable liquid, and could be used for the production of hydrocarbons by using both homogeneous and heterogeneous catalytic systems. The selective reduction of levulinic acid (LA) to GVL is a key transformation for biorefinery concepts based on platform molecules. We report a detailed investigation of the conversion of LA to GVL using molecular hydrogen in the presence of a catalyst in situ generated from Ru(acac)3, and electronically and sterically characterized alkyl-bis(m-sulfonated-phenyl)- and dialkyl-(m-sulfonated-phenyl)phosphine (RnP(C6H4-m-SO3Na)3-n (n = 1 or 2; R = Me, Pr, iPr, Bu, Cp) ligands. The hydrogenation experiments were performed in the range of 5-100 bar H2 at 140 °C using 0.016 mol% catalyst and 5-20 eqv. of ligand. The effects of hydrogen pressure and Ru/ligand ratio on the LA conversion were determined. The nBuP(C 6H4-m-SO3Na)2 (χ = 12.5, Tol = 153°) showed the highest activity achieving turnover numbers up to 6200 with a yield and selectivity higher than 99% in a solvent, chlorine and promoter free reaction mixture. The catalyst was successfully recycled for six consecutive runs without loss of activity. The characterization of sulfonated and non-sulfonated phosphines indicated that the sulfonation had no significant effect on the steric and electronic properties of the ligands. The Royal Society of Chemistry 2012.
OPTISCH AKTIVE PHOSPHINE DURCH ASYMMETRISCHE SUBSTITUTION PROCHIRALER, HOMOCHIRAL SUBSTITUIERTER PHOSPHONITE
Neuffer, J.,Richter, W. J.
, p. 289 - 298 (2007/10/02)
Phenylphosphonous acid dimenthylester and its dibornylester react with bulky nucleophiles to give diastereomeric phosphinous acid esters.The asymmetric induction is as high as 95 percent d.e.If reaction conditions favouring inversion at phosphorus are used then the (R)-menthoxy group of the prochiral starting material is substituted.The phosphinous acid ester can be converted, with partial racemization, into optically active Horner-phosphines.
SYNTHESE UND UMLAGERUNGSREAKTIONEN VON o-FUNKTIONELLEN PHENYLLITHIUM- UND PHENYLNATRIUM DERIVATEN DER IVB UND VB-ELEMENTE
Heinicke, J.,Nietzschmann, E.,Tzschach, A.
, p. 1 - 8 (2007/10/02)
While o-substituted bromobenzene derivatives of the type o-BrC6H4XERn (X = O, S; ERn = SiMe3) and n-BuLi undergo metal halogen exchange followed by silyl-X -> C rearrangement, the corresponding compounds of phosphorus, arsenic or tin are split at the E-X bond. o-Metal derivatives o-MI-C6H4XERn (X = O, NMe; E = P, As, Sn) of these elements may be generated, however, by direct reaction with sodium or lithium.They are unstable and furnish o-hydroxy- and o-aminophenyl element(IV, V) derivatives via an intramolecular anionic rearrangement.
