20491-53-6Relevant articles and documents
Parallels between Metal-Ligand Cooperativity and Frustrated Lewis Pairs
Habraken, Evi R. M.,Jupp, Andrew R.,Brands, Maria B.,Nieger, Martin,Ehlers, Andreas W.,Slootweg, J. Chris
, p. 2436 - 2442 (2019)
Metal ligand cooperativity (MLC) and frustrated Lewis pair (FLP) chemistry both feature the cooperative action of a Lewis acidic and a Lewis basic site on a substrate. A lot of work has been carried out in the field of FLPs to prevent Lewis adduct formation, which often reduces the FLP reactivity. Parallels are drawn between the two systems by looking at their reactivity with CO2, and we explore the role of steric bulk in preventing dimer formation in MLC systems.
Enantioselective addition of secondary phosphines to methacrylonitrile: Catalysis and mechanism
Sadow, Aaron D.,Togni, Antonio
, p. 17012 - 17024 (2005)
A highly enantioselective intermolecular hydrophosphination reaction is described. The (Pigiphos)-nickel(II)-catalyzed reaction of secondary phosphines and methacrylonitrile gives chiral 2-cyanopropylphosphines in good yield and high enantiomeric excess (ee's up to 94%; (R)-(S)-Pigiphos = bis{(R)-1-[(S)-2-(diphenylphosphino)ferrocenyl]ethyl}cyclohexylphos phine). We propose a mechanism involving coordination of methacrylonitrile to the dicationic nickel catalyst followed by 1,4-addition of the phosphine, and then, rate-determining proton transfer. This mechanism is supported by (a) the experimentally determined rate law (rate = K[Ni][methacrylonitrile][t-Bu 2PH]), (b) a large primary deuterium isotope effect K H/KD = 4.6(1) for the addition of t-Bu2PH(D) at 28.3°C in toluene-d8, (c) the isolation and characterization of the species [Ni(K3-Pigiphos)(KN-methacrylonitrile)]2+, and (d) DFT calculations of model compounds.
N,N-BIS(2-DIALKYLPHOSPHINOETHYL)AMINE-BORANE COMPLEX AND PRODUCTION METHOD THEREFOR, AND METHOD FOR PRODUCING RUTHENIUM COMPLEX CONTAINING N,N-BIS(2-DIALKYLPHOSPHINOETHYL)AMINE AS LIGAND
-
Paragraph 0164; 0165-0169, (2019/02/19)
The purpose of the present invention is to provide an N,N-bis(2-dialkylphosphinoethyl)amine-borane complex which is a ruthenium complex that exhibits excellent catalytic activity in a hydrogenation reaction, etc., and a production method therefor, and a method for efficiently producing a ruthenium complex containing N,N-bis(2-dialkylphosphinoethyl)amine as a ligand. The present invention is capable of efficiently producing an amine-borane complex (3) by reacting an oxazolidinone compound (1) with a dialkylphosphine-borane compound (2) in the presence of a base. The present invention is also capable of efficiently producing a ruthenium complex (5) by reacting the amine-borane complex (3) with a ruthenium compound (4) in the presence of an amine. (In the formula, a solid line, a dashed line, B, C, H, L1-L3, LG, n, N, O, P, Ru, X, and R1-R10 are as defined in the description.)
A Universally Applicable Methodology for the Gram-Scale Synthesis of Primary, Secondary, and Tertiary Phosphines
Rinehart, N. Ian,Kendall, Alexander J.,Tyler, David R.
supporting information, p. 182 - 190 (2018/02/06)
Although organophosphine syntheses have been known for the better part of a century, the synthesis of phosphines still represents an arduous task for even veteran synthetic chemists. Phosphines as a class of compounds vary greatly in their air sensitivity, and the misconception that it is trivial or even easy for a novice chemist to attempt a seemingly straightforward synthesis can have disastrous results. To simplify the task, we have previously developed a methodology that uses benchtop intermediates to access a wide variety of phosphine oxides (an immediate precursor to phosphines). This synthetic approach saves the air-free handling until the last step (reduction to and isolation of the phosphine). Presented herein is a complete general procedure for the facile reduction of phosphonates, phosphinates, and phosphine oxides to primary, secondary, and tertiary phosphines using aluminum hydride reducing agents. The electrophilic reducing agents (iBu)2AlH and AlH3 were determined to be vastly superior to LiAlH4 for reduction selectivity and reactivity. Notably, it was determined that AlH3 is capable of reducing the exceptionally resistant tricyclohexylphosphine oxide, even though LiAlH4 and (iBu)2AlH were not. Using this new procedure, gram-scale reactions to synthesize a representative range of primary, secondary, and tertiary phosphines (including volatile phosphines) were achieved reproducibly with excellent yields and unmatched purity without the need for a purification step.
