118575-87-4

Upstream product

• 18031-40-8 (S)-(-)-perillaldehyde 
• 18107-18-1 diazomethyl-trimethyl-silane 
• 19493-09-5 Methylenetriphenylphosphorane 
• 2065-66-9 methyl-triphenylphosphonium iodide 

Downstream Products

• 118575-88-5 4(R,S)-(Phenylthio)-6(S)-isopropenyl-1⁽⁹⁾-octalin 

Relevant academic research and scientific papers

Rhodium-catalyzed synthesis of terminal alkenes

Terminal alkenes have been efficiently prepared via a rhodium-catalyzed olefination procedure using Wilkinson's catalyst in the presence of triphenylphosphine, 2-propanol and trimethylsilyldiazomethane. Optimized reaction conditions are described for aldehydes and ketones, as well as alternative work up procedures. Georg Thieme Verlag Stuttgart.

Electro-mediated PhotoRedox Catalysis for Selective C(sp3)–O Cleavages of Phosphinated Alcohols to Carbanions

We report a novel example of electro-mediated photoredox catalysis (e-PRC) in the reductive cleavage of C(sp3)?O bonds of phosphinated alcohols to alkyl carbanions. As well as deoxygenations, olefinations are reported which are E-selective and can be made Z-selective in a tandem reduction/photosensitization process where both steps are photoelectrochemically promoted. Spectroscopy, computation, and catalyst structural variations reveal that our new naphthalene monoimide-type catalyst allows for an intimate dispersive precomplexation of its radical anion form with the phosphinate substrate, facilitating a reactivity-determining C(sp3)?O cleavage. Surprisingly and in contrast to previously reported photoexcited radical anion chemistries, our conditions tolerate aryl chlorides/bromides and do not give rise to Birch-type reductions.

Copper-carbene complexes as catalysts in the synthesis of functionalized styrenes and aliphatic alkenes

(NHC)-Cu (NHC = N-heterocyclic carbene) complexes efficiently catalyzed the methylenation of a variety of aliphatic and aromatic aldehydes and ketones in the presence of trimethylsilyldiazomethane, triphenylphosphine, and 2-propanol. The copper catalysts are not only inexpensive compared to rhodium complexes, but they also exhibit better functional group compatibility with aromatic aldehydes and ketones. Indeed very high yields were obtained for the formation of styrenes containing nitro, trifluoromethyl, amino, and ester groups, as well as for pyridine-, pyrrole-, and indole-substituted alkenes.

Rhodium-Catalyzed Methylenation of Aldehydes

The rhodium-catalyzed methylenation of aldehydes using trimethylsilyldiazomethane and triphenylphosphine produces a variety of terminal alkenes in excellent yields. These mild and nonbasic reaction conditions allow the conversion of enolizable substrates (keto aldehydes and nonracemic α-substituted aldehydes) to terminal alkenes without epimerization. Optimization of the reaction conditions led to the conclusion that a variety of rhodium(I) sources can be used as catalysts. The effect of the solvent on the reaction has also been studied, and it indicates that although the THF is the best solvent, other solvents may be used. The reactivity of the system is very much dependent on the nature of the phosphine reagent. The use of an easily removable phosphine is also described. Spectroscopic studies indicate that the reaction proceeds via an unusual mechanism which leads to the in situ formation of the salt-free phosphorus ylide, methylenetriphenylphosphorane.

Is hole transfer involved in metalloporphyrin-catalyzed epoxidation?

The possibility of a hole-transfer mechanism for the epoxidation of alkenes catalyzed by metalloporphyrins (MP) has been investigated. In the first approach, the results of MP-catalyzed epoxidation of a series of substrates were compared to the corresponding results of epoxidation under conditions where cation radicals are demonstrably formed (using a triarylaminium salt catalyst). In sharp contrast to the MP-catalyzed epoxidations (using M = Mn), the hole-catalyzed epoxidations do not generate carbonyl compounds and alcohols as byproducts and are rigorously stereospecific. These results are of interest primarily in that they provide support for the assumption that cation radicals can be efficiently and stereospecifically epoxidized by appropriate oxygen-transfer agents. However, the differences in product composition and stereochemistry for MP- vs hole-catalyzed epoxidation cannot be construed mechanistically to rule out a cation radical mechanism for the former, especially because the oxygen-transfer agents are different in the two reaction systems. In a second, and more rigorous, approach, a careful search for transient cation radical intermediates in MP-catalyzed epoxidations (using M = Mn and Fe) was carried out using newly developed cation radical probe reactions. Cation radical intermediates were, in fact, not detected and, if involved, must be extremely short lived (-2 s). The results of this work, taken as a whole, are reasonably construed to suggest that, even for the relatively easily ionizable alkene functionalities present in many of the probe substrates, a hole-transfer mechanism is probably not operative in MP-catalyzed epoxidations.

Cation Radical Diels-Alder Cycloadditions in Organic Synthesis of (-)-β-Selinene

The site-specific, regiospecific, and Diels-Alder periselective hole-catalyzed addition of phenyl vinyl sulfide to (S)-(-)-1-ethenyl-4-isopropenylcyclohexene is shown to provide a very direct route to the sesquiterpenoid natural product (-)-β-selinene.The