Remarkable tolerance of ethynyl steroids to air and water in microwave-assisted hydrophosphinylation: Reaction scope and limitations

Stockland, Robert A.; Lipman, Adam J.; Bawiec, John A.; Morrison, Peter E.; Guzei, Ilia A.; Findeis, Peter M.; Tamblin, John F.

doi:10.1016/j.jorganchem.2006.06.007

Cited by 26 publications

(11 citation statements)

References 65 publications

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“…70-73 Furthermore, propargyl alcohols react with a variety of compounds containing labile P-H groups to generate a number of different products through dehydration, 74 substitution, 75 and hydrophosphinylation. 76, 77 To investigate whether or not the propargyl alcohol could circumvent the P-H activation through alternate chemical reaction pathways or inhibit the process by sequestering the phosphite through simple hydrogen bonding, a range of alkynylgold complexes containing triphenylphosphine (9-12), JohnPhos (16,17), tBuXPhos (21), and SIMes (28)(29)(30)(31) were generated (Table 1) and screened for reactivity towards diethylphosphite.…”

Section: P-h Activation Studiesmentioning

confidence: 99%

P–H activation using alkynylgold substrates: steric and electronic effects

et al. 2011

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The susceptibility of a prototypical hydrogen phosphonate to undergo P-H activation upon treatment with alkynylgold complexes has been studied. Dynamic solution behavior was observed during reactions involving triphenylphosphine ligated substrates and was attributed to rapid phosphine exchange between the alkynylgold starting material and the gold phosphonate product. The use of bulky biaryldialkylphosphine ligands eliminated the fluxional behavior, but did not significantly slow the rate of P-H activation. Similarly, changing the supporting ligand to an N-heterocyclic carbene did not significantly slow the rate of the reaction. Despite a number of reports outlining the functionalization of propargyl alcohols using gold catalysts, incorporating these groups into the architecture of the alkynylgold substrates did not alter the product distributions. Although the chemistry tolerated a range of supporting ligands, incorporating electron donating groups into the alkyne increased the rate of the reaction while electron-withdrawing groups slowed the reaction. A possible mechanism for the process includes a transition state containing significant pi-contribution from the alkyne. Due to the high yields of gold phosphonates obtained in this chemistry as well as the mild conditions of the reactions, the interception of intermediates/catalysts by substrates or ligands containing labile P-H donors is an issue that must be circumvented when designing or developing a gold catalyzed reaction that proceeds through alkynylgold intermediates.

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Section: P-h Activation Studiesmentioning

confidence: 99%

P–H activation using alkynylgold substrates: steric and electronic effects

et al. 2011

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“…In 2004, Nishibayashi and Uemura revealed a double phosphinylation reaction of propargyl alcohols with Ph 2 P(O)H catalyzed by a diruthenium complex [21]. Stockland also investigated the hydrophosphinylation of propargyl alcohols under solvent-free, microwave irradiation conditions in 2006 [22]. Finally, a palladium catalyst and a rhodium catalyst can also selectively produce a-iminophosphine oxides 11 and bisphosphinoylaminomethanes 12, respectively, via metal-mediated insertions of isocyanides to HeP(O) bonds (Scheme 10) [23].…”

Section: Addition Of Secondary Phosphine Oxides R 2 P(o)h To Alkynesmentioning

confidence: 99%

Metal-catalyzed additions of H–P(O) bonds to carbon–carbon unsaturated bonds

Han

2011

Journal of Organometallic Chemistry

124

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“…More recently, Stockland and coworkers applied microwave heating to the addition of secondary phosphine oxides to propargyl alcohols and ethynyl steroids, in the presence of rhodium as catalyst, in various solvents. [xliv] Ethynyl steroids showed very good reactivity under these conditions to afford anti-Markovnikov addition products 2 in high yields (71–86 % depending on the solvent, Scheme 19). …”

Section: Addition Of Secondary Phosphine Oxides R1r2p(o)hmentioning

confidence: 99%

Recent Developments in the Addition of Phosphinylidene‐Containing Compounds to Unactivated Unsaturated Hydrocarbons: Phosphorus–Carbon Bond Formation by Hydrophosphinylation and Related Processes

2008

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Summary The reactions of phosphinylidene-containing compounds with unactivated unsaturated hydrocarbons are reviewed. The review is organized by phosphorus-containing functional group types. Free-radical and metal-catalyzed additions of R1R2P(O)H to alkenes, alkynes, and related compounds, deliver functionalized organophosphorus compounds RP(O)R1R2, including H-phosphinates, phosphinates, tertiary phosphine oxides, and phosphonates. The review covers the literature up to February 2008.

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Remarkable tolerance of ethynyl steroids to air and water in microwave-assisted hydrophosphinylation: Reaction scope and limitations

Cited by 26 publications

References 65 publications

P–H activation using alkynylgold substrates: steric and electronic effects

P–H activation using alkynylgold substrates: steric and electronic effects

Metal-catalyzed additions of H–P(O) bonds to carbon–carbon unsaturated bonds

Recent Developments in the Addition of Phosphinylidene‐Containing Compounds to Unactivated Unsaturated Hydrocarbons: Phosphorus–Carbon Bond Formation by Hydrophosphinylation and Related Processes

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