- A Mild One-Pot Reduction of Phosphine(V) Oxides Affording Phosphines(III) and Their Metal Catalysts
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The metal-free reduction of a range of phosphine(V) oxides employing oxalyl chloride as an activating agent and hexachlorodisilane as reducing reagent has been achieved under mild reaction conditions. The method was successfully applied to the reduction of industrial waste byproduct triphenylphosphine(V) oxide, closing the phosphorus cycle to cleanly regenerate triphenylphosphine(III). Mechanistic studies and quantum chemical calculations support the attack of the dissociated chloride anion of intermediated phosphonium salt at the silicon of the disilane as the rate-limiting step for deprotection. The exquisite purity of the resultant phosphine(III) ligands after the simple removal of volatiles under reduced pressure circumvents laborious purification prior to metalation and has permitted the facile formation of important transition metal catalysts.
- Kapu?niak, ?ukasz,Plessow, Philipp N.,Trzybiński, Damian,Wo?niak, Krzysztof,Hofmann, Peter,Jolly, Phillip Iain
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p. 693 - 701
(2021/04/06)
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- Palladium-Catalyzed C-P(III) Bond Formation by Coupling ArBr/ArOTf with Acylphosphines
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Palladium-catalyzed C-P bond formation reaction of ArBr/ArOTf using acylphosphines as differential phosphination reagents is reported. The acylphosphines show practicable reactivity with ArBr and ArOTf as the phosphination reagents, though they are inert to the air and moisture. The reaction affords trivalent phosphines directly in good yields with a broad substrate scope and functional group tolerance. This reaction discloses the acylphosphines' capability as new phosphorus sources for the direct synthesis of trivalent phosphines.
- Chen, Xingyu,Wu, Hongyu,Yu, Rongrong,Zhu, Hong,Wang, Zhiqian
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p. 8987 - 8996
(2021/06/30)
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- Rhodium-Catalyzed PIII-Directed ortho-C?H Borylation of Arylphosphines
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Transition-metal-mediated metalation of an aromatic C?H bond that is adjacent to a tertiary phosphine group in arylphosphines via a four-membered chelate ring was first discovered in 1968. Herein, we overcome a long-standing problem with the ortho-C?H activation of arylphosphines in a catalytic fashion. In particular, we developed a rhodium-catalyzed ortho-selective C?H borylation of various commercially available arylphosphines with B2pin2 through PIII-chelation-assisted C?H activation. This discovery is suggestive of a generic platform that could enable the late-stage modification of readily accessible arylphosphines.
- Wen, Jian,Wang, Dingyi,Qian, Jiasheng,Wang, Di,Zhu, Chendan,Zhao, Yue,Shi, Zhuangzhi
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supporting information
p. 2078 - 2082
(2019/02/01)
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- Chemoselective Reduction of Phosphine Oxides by 1,3-Diphenyl-Disiloxane
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Reduction of phosphine oxides to the corresponding phosphines represents the most straightforward method to prepare these valuable reagents. However, existing methods to reduce phosphine oxides suffer from inadequate chemoselectivity due to the strength of the P=O bond and/or poor atom economy. Herein, we report the discovery of the most powerful chemoselective reductant for this transformation to date, 1,3-diphenyl-disiloxane (DPDS). Additive-free DPDS selectively reduces both secondary and tertiary phosphine oxides with retention of configuration even in the presence of aldehyde, nitro, ester, α,β-unsaturated carbonyls, azocarboxylates, and cyano functional groups. Arrhenius analysis indicates that the activation barrier for reduction by DPDS is significantly lower than any previously calculated silane reduction system. Inclusion of a catalytic Br?nsted acid further reduced the activation barrier and led to the first silane-mediated reduction of acyclic phosphine oxides at room temperature.
- Buonomo, Joseph A.,Eiden, Carter G.,Aldrich, Courtney C.
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supporting information
p. 14434 - 14438
(2017/10/23)
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- Preparation of Aryl(dicyclohexyl)phosphines by C-P Bond-Forming Cross-Coupling in Water Catalyzed by an Amphiphilic-Resin-Supported Palladium Complex
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Aryl(dicyclohexyl)phosphines were prepared by a catalytic C-P bond-forming cross-coupling reaction of haloarenes with dicyclohexylphosphine under heterogeneous conditions in water containing an immobilized palladium complex coordinated to an amphiphilic polystyrene-poly(ethylene glycol) resin supported di(tert -butyl)phosphine ligand.
- Hirai, Yoshinori,Uozumi, Yasuhiro
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supporting information
p. 2966 - 2970
(2017/10/26)
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- Palladium-catalyzed P(O)R2 directed C-H arylation to synthesize electron-rich polyaromatic monophosphorus ligands
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Palladium-catalyzed arylation of (diisopropylphosphoryl)biphenyl skeleton derivatives by the P(O)R2 directed C-H functionalization was reported. The related products were obtained in high regioselectivity and good functional group tolerance was observed. This reaction provided a new and efficient pathway for the synthesis of polyaromatic monophosphorus ligands. The Royal Society of Chemistry.
- Hu, Rong-Bin,Zhang, Heng,Zhang, Xiao-Yu,Yang, Shang-Dong
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supporting information
p. 2193 - 2195
(2014/02/14)
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- Pd(II)-catalyzed C(sp2)-H hydroxylation with R 2(O)P-coordinating group
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A novel R2(O)P-directed Pd(II)-catalyzed C-H hydroxylation to synthesize various substituted 2′-phosphorylbiphenyl-2-ol compounds is described. Notably, the reaction operates under mild conditions and shows good functional group tolerance, high selectivity, and yield.
- Zhang, Hong-Yu,Yi, Hong-Ming,Wang, Gang-Wei,Yang, Bin,Yang, Shang-Dong
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p. 6186 - 6189
(2014/01/17)
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- Catalyst-free alcoholysis of phosphane-boranes: a smooth, cheap, and efficient deprotection procedure
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Catalyst-free alcoholytic deprotection of borane-protected phosphorus compounds offers a smooth, efficient, and clean alternative to existing deprotection methods. In this paper we report our results on the general applicability of deprotecting phosphane-
- Van Overschelde, Michel,Vervecken, Elias,Modha, Sachin G.,Cogen, Simon,Van der Eycken, Erik,Van der Eycken, Johan
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experimental part
p. 6410 - 6415
(2009/12/09)
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- Process for producing biarylphosphine compound
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A process for producing a biarylphosphine compound is disclosed. The process has a step of subjecting a biarylsulfonate compound to coupling reaction with a hydrogen-phosphine compound in the presence of a catalyst and an organic strong base to obtain a biarylphosphine compound. As the catalyst, preferably used is a nickel compound or a palladium compound. As the organic strong base, preferably used is 1,8-diazabicyclo[5.4.0]undecene-7 (DBU).
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Page/Page column 6-7
(2009/04/24)
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- Reduction of tertiary phosphine oxides with DIBAL-H
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(Chemical Equation Presented) The reduction of tertiary phosphine oxides (TPOs) and sulfides with diisobutylaluminum hydride (DIBAL-II) has been studied in detail. An extensive solvent screen has revealed that hindered aliphatic ethers, such as MTBE, are optimum for this reaction at ambient temperature. Many TPOs undergo considerable reduction at ambient temperature and then stall due to inhibition. 31P and 13C NMR studies using isotopically labeled substrates as well as competition studies have revealed that the source of this inhibition is tetraisobutyldialuminoxane (TIBAO), which builds up as the reaction proceeds. TIBAO selectively coordinates the TPO starting material, preventing further reduction. Several strategies have been found to circumvent this inhibition and obtain full conversion with this extremely inexpensive reducing agent for the first time. Practical reduction protocols for these critical targets have been developed.
- Busacca, Carl A.,Raju, Ravinder,Grinberg, Nelu,Haddad, Nizar,James-Jones, Paul,Lee, Heewon,Lorenz, Jon C.,Saha, Anjan,Senanayake, Chris H.
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p. 1524 - 1531
(2008/04/12)
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- Highly active palladium catalysts for Suzuki coupling reactions
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Mixtures of palladium acetate and o-(di-tert-butylphosphino)biphenyl (4) catalyze the room-temperature Suzuki coupling of aryl bromides and aryl chlorides with 0.5-1.0 mol % Pd. Use of o-(dicyclohexylphosphino)biphenyl (2) allows Suzuki couplings to be carried out at low catalyst loadings (0.000001-0.02 mol % Pd). The process tolerates a broad range of functional groups and substrate combinations including the use of sterically hindered substrates. This is the most active catalyst system in terms of reaction temperature, turnover number, and steric tolerance which has been reported to date.
- Wolfe, John P.,Singer, Robert A.,Yang, Bryant H.,Buchwald, Stephen L.
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p. 9550 - 9561
(2007/10/03)
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