35144-01-5Relevant 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.
Formation of unexpected heterocyclic products from pyrolysis of thiocarbonyl stabilised phosphonium ylides
Aitken, R. Alan,Barker, Graeme,Cleghorn, Lee P.,Reid, Euan J.,Roberts, Sheryl S.
, p. 1135 - 1147 (2014/01/17)
Chiral phthalimido thioxo-stabilised phosphonium ylides, prepared starting from (S)-alanine and (S)-phenylalanine, undergo intramolecular Wittig reaction upon pyrolysis leading to the previously unknown pyrrolo[2,1-a]isoindol-5-one-2- thiones, rather than
Catalyzing pyramidal inversion: Configurational lability of P-stereogenic phosphines via single electron oxidation
Reichl, Kyle D.,Ess, Daniel H.,Radosevich, Alexander T.
supporting information, p. 9354 - 9357 (2013/07/25)
We report that pyramidal inversion of trivalent phosphines may be catalyzed by single electron oxidation. Specifically, a series of P-stereogenic (aryl)methylphenyl phosphines are shown to undergo rapid racemization at ambient temperature when exposed to catalytic quantities of a single electron oxidant in solution. Under these conditions, transient phosphoniumyl radical cations (R3P?+) are formed, and computational models indicate that the pyramidal inversion barriers for these open-shell intermediates are on the order of ~5 kcal/mol. The observed 1020-fold rate enhancement over uncatalyzed pyramidal inversion opens new opportunities for the dynamic stereochemistry of phosphines and may hold additional implications for the configurational stability of P-stereogenic phosphine ligands on high-valent oxidizing transition metals.
Identification of a key intermediate in the asymmetric Appel process: One pot stereoselective synthesis of P-stereogenic phosphines and phosphine boranes from racemic phosphine oxides
Rajendran, Kamalraj V.,Gilheany, Declan G.
supporting information, p. 10040 - 10042 (2012/11/07)
Sequential treatment of racemic phosphine oxides with oxalyl chloride and chiral non-racemic alcohol generates the same ratios of diastereomeric alkoxyphosphonium salts obtained in the corresponding asymmetric Appel process, strongly implicating the intermediate chlorophosphonium salt in the stereoselecting step. Subsequent reduction allows a novel synthesis of enantioenriched P-stereogenic phosphines-phosphine boranes. The Royal Society of Chemistry 2012.
PROCESSES FOR THE STEREOSELECTIVE PREPARATION OF P-CHIRAL FOUR -COORDINATED PHOSPHORUS BORANE COMPOUNDS AND P-CHIRAL THREE-COORDINATED PHOSPHORUS COMPOUNDS
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Page/Page column 55-56, (2012/09/11)
Processes for the stereoselective preparation of P-chiral four-coordinated phosphorus borane compounds and P-chiral three-coordinated phosphorus compounds.
A convenient and mild chromatography-free method for the purification of the products of Wittig and Appel reactions
Byrne, Peter A.,Rajendran, Kamalraj V.,Muldoon, Jimmy,Gilheany, Declan G.
supporting information; experimental part, p. 3531 - 3537 (2012/05/20)
A mild method for the facile removal of phosphine oxide from the crude products of Wittig and Appel reactions is described. Work-up with oxalyl chloride to generate insoluble chlorophosphonium salt (CPS) yields phosphorus-free products for a wide variety of these reactions. The CPS product can be further converted into phosphine.
Enantiodivergent synthesis of P-chirogenic phosphines
Chaux, Fanny,Frynas, Slawomir,Laureano, Hugo,Salomon, Christine,Morata, Gérald,Auclair, Marie-Laure,Stephan, Michel,Merds, Rachid,Richard, Philippe,Ondel-Eymin, Marie-Jo,Henry, Jean-Christophe,Bayardon, Jér?me,Darcel, Christophe,Jugé, Sylvain
, p. 1213 - 1226 (2011/10/31)
Several approaches for the enantiodivergent synthesis of P-chirogenic mono- and diphosphines are described, using ephedrine methodology and phosphine borane chemistry. Firstly, both enantiomers of a tertiary phosphine can be obtained starting from the same oxazaphospholidine borane complex, prepared from (+)-ephedrine, when changing the order of addition of the organolithium reagents during the synthetic pathway. The second approach is based on the chlorophosphine boranes, which react with an organolithium reagent, to afford the corresponding phosphines with inversion of configuration. In the case where the chlorophosphine borane reacts with the t-butyl lithium reagent, a metal-halogen exchange occurs to afford the corresponding phosphide borane with retention of the configuration. The reaction of the phosphide borane with an alkyl halide leads to the same phosphine, but with the opposite configuration. Another approach depends on the diastereoselective preparation of the starting oxazaphospholidine borane complex from (-)-ephedrine, which leads according the case, to either one or the other enantiomer of a phosphine. Finally, the synthesis of (R,R)- and (S,S)-1,2-bis(methylphenylphosphino)ethane is also demonstrated using both enantiomers of the P-chirogenic diphosphinite diborane, which simultaneously allows the introduction of alkyl- or aryl substituents on the phosphorus atoms. In summary, these approaches show the great efficiency of the "ephedrine methodology" for the enantiodivergent synthesis of P-chirogenic mono- and diphosphines, and bearing alkyl or aryl substituents.
Synthesis of P-stereogenic phosphorus compounds. Asymmetric oxidation of phosphines under appel conditions
Bergin, Enda,O'Connor, Cormac T.,Robinson, Shane B.,McGarrigle, Eoghan M.,O'Mahony, Colm P.,Gilheany, Declan G.
, p. 9566 - 9567 (2008/02/13)
Racemic phosphines are converted into enantioenriched phosphine oxides via a synthetically simple, but theoretically interesting, oxidation procedure in good enantiomeric excess (up to 80%) and excellent yields (>95%). These phosphine oxides can be oxidatively coupled to provide easy access to enantiopure DiPAMPO analogues. Particularly attractive aspects of this procedure are the operational simplicity and the low cost required to synthesize these high value compounds. Copyright
Stereospecific deoxygenation of phosphine oxides with retention of configuration using triphenylphosphine or triethyl phosphite as an oxygen acceptor
Wu, Hai-Chen,Yu, Jin-Quan,Spencer, Jonathan B.
, p. 4675 - 4678 (2007/10/03)
(Chemical Equation Presented) A new protocol for deoxygenation of various phosphine oxides with retention of configuration is described. The advantage of the new method includes milder conditions and considerably shortened reaction times. Mechanistic studies about the oxygen transfer between the starting phosphine oxide and the sacrificial triphenylphosphine are also presented.
Radical-based reduction of phosphine sulfides and phosphine selenides by (Me3Si)3SiH
Romeo,Wozniak,Chatgilialoglu
, p. 9899 - 9902 (2007/10/03)
Tris(trimethylsilyl)silane reacts with phosphine sulfides and phosphine selenides under free radical conditions to give the corresponding phosphines in good yields. Stereochemical studies on P-chiral phosphine sulfides show these reductions proceed with retention of configuration. (C) 2000 Elsevier Science Ltd.
