- Copper-Catalyzed C?P Cross-Coupling of (Cyclo)alkenyl/Aryl Bromides and Secondary Phosphine Oxides with in situ Halogen Exchange
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An efficient protocol for concurrent tandem halogen exchange/C?P cross-coupling of cycloalkenyl bromides and secondary phosphine oxides has been developed. The catalytic system is based on cheap and air-stable copper(I) iodide as the precatalyst, commercially available N,N’-dimethylethylenediamine as the ligand, and Cs2CO3 or K2CO3 as the base. The use of sodium iodide as an additive reduces the excessive use of organic bromides to near-stoichiometric by promoting the in situ transformation to the corresponding iodides. Diarylphosphine oxides undergo cycloalkenylation with 35–99 % yields and dicyclohexylphosphine oxide with 30–53 % yields. In the case of acyclic alkenyl bromides the cross-coupling products undergo conjugate addition of diphenylphosphine oxide and satisfying yields are observed only for internal olefins. In the case of aryl bromides satisfying yields (43–72 %) are observed only for sterically unhindered arenes or arenes possessing an ortho-directing group. Cycloalkenylphosphine oxides prepared in the cross-coupling reaction undergo base-catalyzed and base-promoted conjugate addition to give bis(phosphinoyl)cycloalkanes.
- Stankevi?, Marek,Wo?nicki, Pawe?
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supporting information
p. 3484 - 3491
(2021/07/22)
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- Homolytic substitution at phosphorus for the synthesis of alkyl and aryl phosphanes
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(Chemical Equation Presented) A transition-metal-free radical phosphonation using Me3SnPPh2 and the less toxic Me 3SiPPh2 is reported. These readily available reagents react highly efficiently with primary and secondary alkyl radicals. Moreover, aryl radicals and tertiary alkyl radicals are phosphonated with Me 3SnPPh2 (see scheme; R = aryl, alkyl, vinyl; X = 1, Br, OC(S)imidazolyl). DFT calculations provide insights into the mechanism of the reaction.
- Vaillard, Santiago E.,Mueck-Lichtenfeld, Christian,Grimme, Stefan,Studer, Armido
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p. 6533 - 6536
(2008/09/17)
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- ENEPHOSPHINILATION
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A general method is described for the formation of vinylphosphines from arylsulfonylhydrazones.Oxidation of the resulting vinylphosphines yields phosphine oxides.
- Mislankar, Dattatraya G.,Mugrage, Ben,Darling, S. D.
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p. 4619 - 4622
(2007/10/02)
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