A Novel Synthesis of Dialkyl Arenephosphonates

Hirao, Toshikazu; Masunaga, Toshio; Ohshiro, Yoshiki; Agawa, Toshio

doi:10.1055/s-1981-29335

Cited by 296 publications

(138 citation statements)

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“…The mixture was transferred to a Schlenk flask, degassed by repeated freezepump-thaw cycles, and purged with argon. Tetrakis(triphenylphosphine)-palladium(0) (600 mg) was then added and the mixture was stirred at 90 8C for 7 h. [46] In the course of the coupling reaction, the reaction mixture changed from brown to pale greenish-brown. Diethyl ether was then added to the reaction mixture and the precipitate that formed was filtered off.…”

Section: Methodsmentioning

confidence: 99%

Efficient Charge Injection from the S₂ Photoexcited State of Special‐Pair Mimic Porphyrin Assemblies Anchored on a Titanium‐Modified ITO Anode

Morisue

Haruta

Kalita

et al. 2006

Chemistry A European J

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A novel surface fabrication methodology has been accomplished, aimed at efficient anodic photocurrent generation by a photoexcited porphyrin on an ITO (indium-tin oxide) electrode. The ITO electrode was submitted to a surface sol-gel process with titanium n-butoxide in order to deposit a titanium monolayer. Subsequently, porphyrins were assembled as monolayers on the titanium-treated ITO surface via phosphonate, isophthalate, and thiolate groups. Slipped-cofacial porphyrin dimers, the so-called artificial special pair at the photoreaction center, were organized through imidazolyl-to-zinc complementary coordination of imidazolylporphyrinatozinc(II) units, which were covalently immobilized by ring-closing olefin metathesis of allyl side chains. The modified surfaces were analyzed by means of X-ray photoelectron spectroscopy. Photoirradiation of the porphyrin dimer generated a large anodic photocurrent in aqueous electrolyte solution containing hydroquinone as an electron sacrificer, due to the small reorganization energy of the dimer. The use of different linker groups led to significant differences in the efficiencies of anodic photocurrent generation. The apparent flat-band potentials evaluated from the photocurrent properties at various pH values and under biased conditions imply that the band structure of the ITO electrode is modified by the anchoring species. The quantum yield for the anodic photocurrent generation by photoexcitation at the Soret band is increased to 15 %, a surprisingly high value without a redox cascade structure on the ITO electrode surface, while excitation at the Q band is not so significant. Extensive exploration of the photocurrent properties has revealed that hot injection of the photoexcited electron from the S2 level into the conduction band of the ITO electrode takes place before internal conversion to the S1* state, through the strong electronic communication of the phosphonyl anchor with the sol-gel-modified ITO surface.

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Section: Methodsmentioning

confidence: 99%

Efficient Charge Injection from the S₂ Photoexcited State of Special‐Pair Mimic Porphyrin Assemblies Anchored on a Titanium‐Modified ITO Anode

Morisue

Haruta

Kalita

et al. 2006

Chemistry A European J

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“…5,6 To facilitate synthesis of stereodefined oligonucleotide analogues and other biologically important phosphorus compounds containing a C-P bond, we developed a stereospecific synthesis of dinucleoside phenylphosphonates and phenylphosphonothioates via a palladium cross-coupling reaction. 12,13 This chemistry was applied to the synthesis of dinucleoside phenylphosphonate and phenylphosphonothioate building blocks as shown in Scheme 1.…”

Section: Resultsmentioning

confidence: 99%

DNA oligonucleotides with stereodefined phenylphosphonate and phosphonothioate internucleotide bonds: synthesis and physico-chemical properties

Sobczak¹,

Johansson²,

Bulkowski³

et al. 2011

Arkivoc

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Separate diastereomers of suitably protected dithymidine (3',5')-phenylphosphonates and dithymidine (3',5')-phenylphosphonothioates were obtained via a palladium(0) catalysed stereospecific cross-coupling reaction between separate diastereomers of the corresponding dinucleoside H-phosphonates and dinucleoside H-phosphonothioates with iodobenzene. These compounds were converted into the corresponding phosphoramidite building blocks and used for incorporation of P-stereodefined dithymidine phenylphosphonate and phenylphosphonothioate units TxT into DNA oligonucleotide chain. Dodecathymidylates with centrally positioned one (T 9 TxTT 9 ) or two modified units (T 8 TxTTxTT 8 ) exhibited different affinity towards complementary DNA (dA 20 ) or RNA (A 20 ) strands depending on stereochemistry at the phosphorus center, as determined by UV melting temperature studies. Oligonucleotides containing the R P -phenylphosphonate or R P -phenylphosphonothioate internucleotide linkages exhibited higher binding affinity to the complementary strands than their S P -counterparts, but slightly lower than the non-modified reference T 20 . All phenylphosphonothioate-modified oligonucleotides formed less stable than their oxo-counterparts duplexes. As expected, the cleavage of the oligonucleotides investigated with 3'-and 5'-exonucleases was stalled at the modification site, independently of P-chirality at the modification site.

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“…In the early 1980s, Hirao and coworkers reported a phosphorus-carbon cross-coupling reaction of aryl-and vinyl halides with O,O-dialkyl phosphites in the presence of triethylamine (Et 3 N) and catalytic amount of tetrakis(triphenylphosphine)palladium [Pd(PPh 3 ) 4 ] to synthesize a variety of dialkyl aryl-and vinyl-phosphonates in good yields [10][11][12]. This reaction is now known as the Hirao reaction after the name of the inventor.…”

Section: The Hirao Reactionmentioning

confidence: 99%

Microwave-assisted Hirao reaction: recent developments

Brahmachari

2015

ChemTexts

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Organic molecules containing phosphorus, now, constitute a major branch of chemistry, and offer fascinating possibilities for their structural, synthetic, and mechanistic study as well as promising biological activities. Organophosphorus compounds find numerous potential applications in the areas of industrial, agricultural, and medicinal chemistry. Aryl-and vinyl-phosphonates are an important class of organophosphorus compounds with potential biological relevance. The Hirao reaction offers a way to access these compounds through phosphorus-carbon (P-C) cross-coupling of aryl and vinyl halides with O,O-dialkyl phosphites, and this reaction has attained a commendable development in many ways in regard to the diversity in the substrates, [P(O)H species, catalysts, and reaction conditions. The present article deals with such developments that occurred under the influence of microwave irradiation.

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A Novel Synthesis of Dialkyl Arenephosphonates

Cited by 296 publications

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Efficient Charge Injection from the S₂ Photoexcited State of Special‐Pair Mimic Porphyrin Assemblies Anchored on a Titanium‐Modified ITO Anode

Efficient Charge Injection from the S₂ Photoexcited State of Special‐Pair Mimic Porphyrin Assemblies Anchored on a Titanium‐Modified ITO Anode

DNA oligonucleotides with stereodefined phenylphosphonate and phosphonothioate internucleotide bonds: synthesis and physico-chemical properties

Microwave-assisted Hirao reaction: recent developments

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A Novel Synthesis of Dialkyl Arenephosphonates

Cited by 296 publications

References 0 publications

Efficient Charge Injection from the S2 Photoexcited State of Special‐Pair Mimic Porphyrin Assemblies Anchored on a Titanium‐Modified ITO Anode

Efficient Charge Injection from the S2 Photoexcited State of Special‐Pair Mimic Porphyrin Assemblies Anchored on a Titanium‐Modified ITO Anode

DNA oligonucleotides with stereodefined phenylphosphonate and phosphonothioate internucleotide bonds: synthesis and physico-chemical properties

Microwave-assisted Hirao reaction: recent developments

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Efficient Charge Injection from the S₂ Photoexcited State of Special‐Pair Mimic Porphyrin Assemblies Anchored on a Titanium‐Modified ITO Anode

Efficient Charge Injection from the S₂ Photoexcited State of Special‐Pair Mimic Porphyrin Assemblies Anchored on a Titanium‐Modified ITO Anode