- Aryl group - A leaving group in arylphosphine oxides
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The treatment of triphenylphosphine oxide with organometallic reagents leads to the substitution of up to three phenyl substituents with the incoming carbon nucleophile. The replacement of the phenyl/aryl group in tertiary diarylalkylphosphine oxides or even aryldialkylphosphine oxides was also observed. Naphthyl-substituted phosphine oxides undergo Michael-type addition at the naphthyl group when treated with organolithium reagent.
- Stankevi?, Marek,Pisklak, Jolanta,W?odarczyk, Katarzyna
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p. 810 - 824
(2016/01/20)
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- Synthesis of functionalized 1,4-cyclohexadienes through intramolecular anionic dearomatization of N-alkyl-N-benzyldiphenylphosphinamides. Insight into the reaction mechanism
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A generalization of the intramolecular nucleophilic dearomatization-electrophilic alkylation reactions of N-alkyl-N-benzyldiphenylphosphinamide anions is presented. The process has been optimized by analyzing the effects of metalation and quench times, additives, the nature of the electrophiles used (MeI, CF3SO3Me, Me3O+BF4-, AllylBr, PhCH2Br, BrCH2CO2Me, and RCH=O, where R = Ph, 4-Cl-C6H4, 4-MeO-C6H4, and iPr), and the alkyl substituent linked to the nitrogen of the phosphinamide. Both HMPA and DMPU act as catalysts. The latter proved to be much more efficient for obtaining high yields of substituted tetrahydrobenzo[c] [1,2]-1λ5-phospholes containing a 1,4-cyclohexadiene system with very high regio- and diastereoselectivity. Steric effects in the neighborhood of the benzylic anion tend to decrease the stereoselectivity of the anionic cyclization. The optimization study also served to shed light on the reaction mechanism of the dearomatization process by identifying several intermediate species and showing the reversibility of the anionic cyclization step as well as of the reaction with aldehydes.
- Fernandez, Ignacio,Forcen-Acebal, Angela,Garcia-Granda, Santiago,Lopez-Ortiz, Fernando
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p. 4472 - 4485
(2007/10/03)
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- Synthesis of phosphane oxides and phosphonates by cerium-mediated addition of organolithium compounds to chloro-phosphorus compounds
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The addition of organocerium reagents 2a-g to phosphinoyl chloride 1a or chlorophosphates 1b leads to the synthesis of phosphane oxides 3aa-ag and phosphonates 3bb, be in good to high yield. The reaction can be extended to cerium enolates 4 (of ketones) and 6 (of nitriles) except when a benzyl group bound to the carbonyl moiety should be metallated. The latter reaction is the first reported synthesis of β-oxophosphane oxides by a simple reaction between enolates and a phosphorus(V) halide.
- Dalpozzo, Renato,De Nino, Antonio,Miele, Daniela,Tagarelli, Antonio,Bartoli, Giuseppe
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p. 2299 - 2301
(2007/10/03)
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- Novel Direct Deoxygenation of the Hydroxy Group of (1-Hydroxyalkyl)-diphenylphosphine Oxides
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The hydroxyl group of (1-hydroxyalkyl)-diphenylphosphine oxides 1 is directly deoxygenated on treatment with phosphorus trichloride and iodides to give parent alkyl-diphenylphosphine oxides 2.
- Yamashita, Mitsuji,Suzuki, Takanobu,Imoto, Hiroyuki,Oshikawa, Tatsuo,Inokawa, Saburo
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p. 556 - 557
(2007/10/02)
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- PREPARATION OF DIPHENYLPHOSPHINE OXIDES BY DEOXYGENATION OF AN α-HYDROXYL GROUP WITH DIPHOSPHORUS TETRAIODIDE
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Deoxygenation of (1-hydroxyethyl)diphenylphosphine oxide derivatives was first achieved by a reaction with diphosphorus tetraiodide to give ethyldiphenylphosphine oxide derivatives.The reaction was also successful to prepare cyclohexyldiphenylphosphine oxide.
- Yamashita, Mitsuji,Tsunekawa, Kenji,Sugiura, Motoyuki,Oshikawa, Tatsuo,Inokawa, Saburo
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p. 1673 - 1674
(2007/10/02)
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