703-35-5

Upstream product

• 3310-62-1 2,3-diazabicyclo[2.2.2]oct-2-ene 
• 1165952-91-9 cyclohexa-1,3-diene 
• 100-42-5 styrene 
• 288-53-9 1,3-dioxole 
• 873-66-5 1-propenylbenzene 
• 766-94-9 vinyl phenyl ether 
• 4180-23-8 E-1-(4'-methoxyphenyl)prop-1-ene 

Relevant academic research and scientific papers

Photooxidizing chromium catalysts for promoting radical cation cycloadditions

The photooxidizing capabilities of selected CrIII complexes for promoting radical cation cycloadditions are described. These complexes have sufficiently long-lived excited states to oxidize electron-rich alkenes, thereby initiating [4+2] processes. These metal species augment the spectrum of catalysts explored in photoredox systems, as they feature unique properties that can result in differential reactivity from the more commonly employed ruthenium or iridium catalysts. Spotlight on chromium: Selected CrIII complexes were investigated for promoting radical cation cycloadditions. These species have sufficiently long-lived excited states to oxidize electron-rich alkenes, thereby initiating [4+2] processes. These metal complexes augment the spectrum of catalysts explored in photoredox systems, featuring properties that can result in differential reactivity from the more common Ru or Ir catalysts.

Thermal reaction of cyclic alkadiene with trichlorosilane. Preparative and mechanistic aspects

The thermal reactions of trichlorosilane (1a) with cyclic alkadienes such as cyclopentadiene (2a), 1,3-cyclohexadiene (2b), and 1,4-cyclohexadiene (2c) were studied at temperatures ranging from 170 °C to 250 °C. In this reaction, the hydrosilylation rate increased as the reaction temperature was raised using an equimolar ratio of 1a to 2a. The reaction of 2a with 1a at 250 °C afforded 2-cyclopentenyltrichlorosilane (3a) as the major hydrosilylation product within 1 h in good yield (82%). This reaction also works when dicyclopentadiene (2a′) was used as a reactant instead of 2a. In a large scale preparation under the same conditions, 3a was obtained in 82% isolated yield. It is significant to note that 2a′ can be used for the hydrosilylation, with no requirement of a cracking step under our thermal conditions. While the reaction of cyclohexadienes with 1a under the same conditions gave a mixture of three hydrosilylation products such as 2-cyclohexenyltrichlorosilane (3b), 3-cyclohexenyltrichlorosilane (3c) and cyclohexyltrichlorosilane (5) in moderate yields, along with other unsaturated C6 components, such as benzene and cyclohexene. In the thermal reaction of cycloalkadienes with 1a, the five-membered-ring diene 2a undergoes both a hydrosilylation reaction with 1a as well as a [4 + 2] cycloaddition reaction, leading to the hydrosilylation product 3a in good yield. While the six-membered ring dienes, 2b and 2c, undergo four different types of reactions, including hydrosilylation, [4 + 2] cycloaddition, dehydrogenation, and hydrogenation in competition to give the hydrosilylation products, hexane, and benzene, respectively. The reaction rates of cyclic alkadienes under our thermal conditions increase in the following order: 2c 2b 2a.

Pyrylium Salts as Photosensitizers in Homogeneous and Heterogeneous Electron-Transfer Catalysis. - A Comparison with Cyano Arenes

Two new triphenylpyrylium salts, both being fixed to a polymeric backbone, have been synthesized.They are sensitizers for photochemically induced electron-transfer reactions, offering the possibility of heterogeneous charge transfer.Their usability in electron-transfer-catalyzed dimerizations and mixed cycloadditions of 1,3-cyclohexadiene and phenyl vinyl ether has been tested in comparison to other common photosensitizers such as 9,10-dicyanoanthracene and 1,4-dicyanonaphthalene.In addition, 2,4,6-triphenylpyrylium tetrafluoroborate was shown to operate as an efficient sensitizer for the dimerization and the photooxygenation of 1,1-diphenylethene.Diverse selectivities in the product formation indicate different mechanisms and are discussed in view of earlier results reported in the literature. - Key Words: Electron-transfer photocatalysis / Electron transfer, photoinduced / Photooxygenation / Pyrylium salts, polymeric / Radical cation cycloadditions

ELECTROCHEMICALLY INDUCED -CYCLOADDITIONS - A MECHANISTIC INTERPRETATION OF THE CATION RADICAL DIELS-ALDER REACTION BASED ON PREPARATIVE RESULTS

For the first time it was possible to induce the cation radical Diels-Alder reaction between electronrich dienes and electronrich dienophiles eletrochemically, thus providing a clearer view upon the mechanism of this reaction type.In contrast to common explanations it could be demonstrated that this reaction most probably takes place via the cation radical of the diene.A role selectivity towards the cation radical of the dienophile could be ruled out.

Fluorescence Quenching and Photoreactions of 2,3-Diazabicyclooct-2-enes. A Case of Charge Transfer and Hydrogen Atom Transfer

A variety of organic compounds have been found to quench the long-lived fluorescence of 2,3-diazabicyclooct-2-ene (DBO), but photochemical reactions take place only with good hydrogen atom donors and tetrahalomethanes.A hydrogen isotope effect on kq of 1.7-3.0 was observed with 1,3- and 1,4-cyclohexadiene.While both quenchers photoreduced DBO, the 1,3-isomer also dimerized to a mixture characteristic of triplet diene.The results are rationalized in terms of the usual encounter complex and ion pair except that the former can undergo hydrogen transfer or react with 1,3-cyclohexadiene.A second case of photochemically induced electron transfer fragmentation was found in the reaction of 1-phenyl-DBO with bromotrichloromethane.

A New Type of Electron Acceptor for Diels-Alder Reactions via Radical Cations

Ketone-LiClO4 mixtures have been shown to be effective electron acceptors for catalysing Diels-Alder reactions, which may proceed both via the radical cation of the diene and via the radical cation of the dienophile.