54067-17-3Relevant academic research and scientific papers
A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
Taylor, Nicholas P.,Gonzalez, Jorge A.,Nichol, Gary S.,García-Domínguez, Andrés,Leach, Andrew G.,Lloyd-Jones, Guy C.
supporting information, p. 721 - 729 (2022/01/04)
The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
Reduction of tertiary phosphine oxides to phosphine-boranes using Ti(Oi-Pr)4/BH3-THF
Sowa, Sylwia,Pietrusiewicz, K. Micha?
, (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.
Effectiveness and Mechanism of the Ene(amido) Group in Activating Iron for the Catalytic Asymmetric Transfer Hydrogenation of Ketones
Xue, Qingquan,Wu, Rongliang,Wang, Di,Zhu, Meifang,Zuo, Weiwei
, p. 134 - 147 (2021/02/05)
I-interacting ligands of the diphosphino amido-ene(amido) type are effective in activating iron to resemble the properties of precious metals in the catalytic asymmetric transfer hydrogenation of ketones. To further verify the effectiveness of the ene(amido) group, we synthesized four amine(imine) diphosphine iron precatalyst complexes with substituents at α and β positions relative to imino groups (1-3) or with enlarged chelate ring sizes (5,5,6-membered rings) (4). In comparison with the parent trans-(R,R)-[Fe(CO)(Cl)(PPh2CH2CHaNCHPhCHPhNHCH2CH2PPh2)]BF4 (I), the introduction of a methyl group in 1 and 2 reduced the catalytic activity but led to undiminished enantioselectivity as reaction proceeded. In comparison to the iron complexes 1-3 with a 5,5,5-coordination geometry, the complex 4 derived from the new (R,R)-P-NH-NH2 tridentate ligand showed high reactivity comparable to that of I but was unfortunately not enantioselective. The catalytic reactivity of 1, 2, and 4 illustrates the effectiveness of the ene(amido) group. An electronic structure study on the important catalytic intermediate amido-ene(amido) complex 1b proved that iron was activated by an additional I-back-donation-interaction ligand to participate in the traditional metal-ligand bifunctional pathway in the asymmetric transfer hydrogenation reactions.
Synthesis of Allylboranes via Cu(I)-Catalyzed B-H Insertion of Vinyldiazoacetates into Phosphine-Borane Adducts
Drikermann, Denis,M??el, Robert S.,Al-Jammal, Walid K.,Vilotijevic, Ivan
supporting information, p. 1091 - 1095 (2020/02/15)
Cu(I) catalysts enable C-B bond formation via direct insertion of vinyldiazoacetates into B-H bonds of borane-phosphine Lewis adducts to form phosphine-protected allylboranes under mild conditions. The resulting allylborane-phosphine Lewis adducts can be used in the diastereoselective allylation of aldehydes directly without the need for removal of the phosphine. The allylation reaction proceeds with high diastereoselectivity and yields 5,6-disubstituted dihydropyranones after treatment with an appropriate acid.
Br?nsted Acid Promoted Reduction of Tertiary Phosphine Oxides
Krachko, Tetiana,Lyaskovskyy, Volodymyr,Lutz, Martin,Lammertsma, Koop,Slootweg, J. Chris
, p. 916 - 921 (2017/08/11)
Recently, Br?nsted acids, such as phosphoric acids, carboxylic acids, and triflic acid, were found to catalyze the reduction of phosphine oxides to the corresponding phosphines. In this study, we fully characterize the HCl, HOTf, and Me2SiHOTf adducts of triphenylphosphine oxide and find that the thermally stable adduct Ph3POH+OTf– is efficiently converted into triphenylphosphine at 100 °C in the presence of readily available hydrosiloxanes. Under the same reaction conditions, also Ph3POSiMe2H+OTf– selectively affords triphenylphosphine indicating that silylated phosphine oxides are likely intermediates in this process.
Organocatalyzed Reduction of Tertiary Phosphine Oxides
Schirmer, Marie-Luis,Jopp, Stefan,Holz, Jens,Spannenberg, Anke,Werner, Thomas
supporting information, p. 26 - 29 (2016/01/25)
A novel selective catalytic reduction method of tertiary phosphine oxides to the corresponding phosphines has been developed. Notably, the reaction proceeds smoothly with low catalyst loadings of 1-5 mol% even at low temperature (70 C). Under the optimized conditions various phosphine oxides could be selectively reduced and the desired phosphines were usually obtained in excellent yields above 90%. Furthermore, we have developed a one-pot reaction sequence for the preparation of valuable phosphinborane adducts. Simple addition of BH3THF subsequent to the reduction step gave the desired adducts in yields up to 99%.
Reduction of phosphine oxides to phosphines with the InBr3/TMDS system
Pehlivan, Leyla,Métay, Estelle,Delbrayelle, Dominique,Mignani, Gérard,Lemaire, Marc
supporting information; experimental part, p. 3151 - 3155 (2012/05/31)
An efficient method for the reduction of phosphine oxide derivatives into their corresponding phosphines is described. The system InBr3/TMDS allows the reduction of different secondary and tertiary phosphine oxides as well as aliphatic and aromatic phosphine oxides.
In situ dearomatisation/alkylation of arylphosphane derivatives
Stankevic, Marek,Wojcik, Karolina,Jaklinska, Magdalena,Pietrusiewicz, K. Michal
experimental part, p. 2521 - 2534 (2012/06/01)
The dearomatisation of aryldialkylphosphane-boranes and aryldialkylphosphane oxides under Birch reduction conditions, followed by treatment with reactive alkyl halides, provides the corresponding α-functionalised (cyclohexa-1,4-dien-3-yl)phosphane derivatives. This reaction offers a method of choice for the synthesis of bulky (cyclohexadienyl)phosphanes.
The lithiation and acyl transfer reactions of phosphine oxides, sulfides and boranes in the synthesis of cyclopropanes
Clarke, Celia,Fox, David J.,Pedersen, Daniel Sejer,Warren, Stuart
supporting information; experimental part, p. 1329 - 1336 (2009/12/04)
Phosphine oxides are lithiated much faster than phosphine sulfides and phosphine boranes. Phosphine sulfides are in turn lithiated much more readily than phosphine boranes. It was possible to trap a phosphine sulfide THF in one case which upon treatment with t-BuOK gave cyclopropane, showing that phosphine sulfides readily undergo both phosphinoyl transfer and cyclopropane ring closure just like their phosphine oxide counterparts. The obtained data show that phosphine oxides are easily lithiated and undergo phosphoryl transfer much more readily and faster than phosphine sulfides and phosphine boranes. The observations suggest that it would be possible to perform reactions involving phosphine oxides in the presence of phosphine boranes or phosphine sulfides, potentially allowing regioselective alkylation of phosphine oxides in the presence of phosphine boranes or phosphine sulfides.
Phosphanylborohydrides: First assessment of the relative Lewis basicities of [BH3PPh2]-, CH3PPh2, and HPPh2
Dornhaus, Franz,Bolte, Michael,Lerner, Hans-Wolfram,Wagner, Matthias
, p. 1777 - 1785 (2007/10/03)
The compounds K[PPh2], HPPh2, CH3PPh 2, BH3(H)PPh2, BBr3(H)PPh 2, BH3(CH3)PPh2, BBr 3(CH3)PPh2, [Hsu
