Selective reductions in the sphere of organophosphorus compounds

Keglevich, György; Gaumont, Annie‐Claude; Denis, Jean‐Marc

doi:10.1002/hc.1026

Cited by 19 publications

(10 citation statements)

References 20 publications

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“…At the time, a literature review revealed there were few protocols for phosphane oxide reduction. [24][25][26] Of these methods, most would be unsuitable as a reductant in a proposed CWR: lithium aluminum hydride [25] is a harsh relatively unselective reducing agent and tri-A C H T U N G T R E N N U N G chloroA C H T U N G T R E N N U N G silane (with or without an amine base) [24] has selectivity concerns that stem from the lability of the SiÀCl bond and control of the phosphorus center during the reduction. Yet the solution may be found in a structural relative of trichlorosilane; that is, both phenylsilane and diphenylsilane are known to reduce phosphane oxides and are likely to be compatible with a catalytic Wittig process (Scheme 1).…”

Section: Resultsmentioning

confidence: 99%

Part I: The Development of the Catalytic Wittig Reaction

O’Brien

Nixon²,

Holohan

et al. 2013

Chemistry A European J

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We have developed the first catalytic (in phosphane) Wittig reaction (CWR). The utilization of an organosilane was pivotal for success as it allowed for the chemoselective reduction of a phosphane oxide. Protocol optimization evaluated the phosphane oxide precatalyst structure, loading, organosilane, temperature, solvent, and base. These studies demonstrated that to maintain viable catalytic performance it was necessary to employ cyclic phosphane oxide precatalysts of type 1. Initial substrate studies utilized sodium carbonate as a base, and further experimentation identified N,N-diisopropylethylamine (DIPEA) as a soluble alternative. The use of DIPEA improved the ease of use, broadened the substrate scope, and decreased the precatalyst loading. The optimized protocols were compatible with alkyl, aryl, and heterocyclic (furyl, indolyl, pyridyl, pyrrolyl, and thienyl) aldehydes to produce both di- and trisubstituted olefins in moderate-to-high yields (60-96%) by using a precatalyst loading of 4-10 mol%. Kinetic E/Z selectivity was generally 66:34; complete E selectivity for disubstituted α,β-unsaturated products was achieved through a phosphane-mediated isomerization event. The CWR was applied to the synthesis of 54, a known precursor to the anti-Alzheimer drug donepezil hydrochloride, on a multigram scale (12.2 g, 74% yield). In addition, to our knowledge, the described CWR is the only transition-/heavy-metal-free catalytic olefination process, excluding proton-catalyzed elimination reactions.

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Section: Resultsmentioning

confidence: 99%

Part I: The Development of the Catalytic Wittig Reaction

O’Brien

Nixon²,

Holohan

et al. 2013

Chemistry A European J

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“…This required the first step to be the reduction of phosphine oxide to phosphine. There are few reliable methods to reduce a phosphine oxide; [20][21][22] most either use harsh reducing agents, such as lithium aluminum hydride [21] or trichlorosilane, with or without an amine base. [20] However, we felt that neither of the aforementioned reduction protocols would be compatible with the overall catalytic process.…”

Section: Dedicated To Avner and Marie Obrien (Nøe Yang)mentioning

confidence: 99%

Recycling the Waste: The Development of a Catalytic Wittig Reaction

et al. 2009

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“…C 2015 Wiley Periodicals, Inc. justified by semiempirical calculations [6]. The results of Quin, Mathey, and other authors revealed the importance of the 7-phosphanorbornene derivatives in fragmentation-related phosphorylation reactions [7][8][9], complexations [10][11][12], and in re-functionalizations [13][14][15][16] including deoxygenations [17][18][19]. The Bayer-Villiger oxidation of 7-phosphanorbornenes leads to valuable oxaphosphabicyclo [2.2.2]octene derivatives that may be useful in fragmentation-related phosphorylations [20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Revisiting the 7‐Phospanorbornene Family: New P‐Alkyl Derivatives

Kovács

Fülöp

Mucsi

et al. 2015

Heteroatom Chemistry

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A series of 1‐alkyl‐3‐methyl‐2,5‐dihydro‐1H‐phosphole oxides were converted to the corresponding phosphole oxides that, by the Diels–Alder reaction with N‐maleimide derivatives or with another unit of phosphole oxide, yielded trapped phosphole oxides or phosphole oxide dimers, respectively, as new 7‐phosphanorbornene 7‐oxides. The stereostructures of three derivatives were evaluated by single crystal X‐ray analysis. The regio‐ and stereospecific dimerization was studied by B3LYP/6‐31G(d,p) quantum chemical calculations, whose results were in accord with syntheses. Novel mechanistic features were explored. The geometrical data obtained by single crystal X‐ray analysis validated the results of quantum chemical calculations, as the deviation was less than 3%.

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Selective reductions in the sphere of organophosphorus compounds

Cited by 19 publications

References 20 publications

Part I: The Development of the Catalytic Wittig Reaction

Part I: The Development of the Catalytic Wittig Reaction

Recycling the Waste: The Development of a Catalytic Wittig Reaction

Revisiting the 7‐Phospanorbornene Family: New P‐Alkyl Derivatives

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