6165-55-5Relevant academic research and scientific papers
Investigating the microwave-accelerated Claisen rearrangement of allyl aryl ethers: Scope of the catalysts, solvents, temperatures, and substrates
Hui, Zi,Jiang, Songwei,Qi, Xiang,Ye, Xiang-Yang,Xie, Tian
supporting information, (2020/05/18)
The microwave-accelerated Claisen rearrangement of allyl aryl ethers was investigated, in order to gain insight into the scope of the catalysts, solvents, temperatures, and substrates. Among the catalysts examined, phosphomolybdic acid (PMA) was found to greatly accelerate the reaction in NMP, at temperatures ranging from 220 to 300 °C. This method was found to be useful for preparing several intermediates previously reported in the literature using precious metal catalysts such as Au(I), Ag(I), and Pt(II). Additionally, substrates bearing bromo and nitro groups on the aryl portion required careful tailoring of the reaction conditions to avoid complex product profiles.
Intramolecular Reactions of o-Alkoxy- and o-Alkylthio-benzyl Radicals
Cadogan, J. I. G.,Husband, James B.,McNab Hamish
, p. 697 - 702 (2007/10/02)
We report new gas-phase reactions of o-substituted benzyl radicals produced by flash vacuum pyrolysis of 2,3-dihydro-1,3,2-benzoxazaphosph(V)oles (4)-(6), dibenzyl sulphone (8), and dibenzyl oxalates (9)-(11).Both o-ethoxy- and o-methoxy-benzyl radicals rearrange to o-tolualdehyde via intramolecular hydrogen transfer, as shown by experiments using 2-methoxybenzyl radicals. o-Methylthiobenzyl radicals do not give the corresponding thioaldehyde, but produce a mixture of benzocyclobutene and isomeric dihydrobenzothiophens by novel rearrangement reactions. o-Ethylthio- and o-propylthio-benzyl radicals give o-methylstyrene and o-propenyltoluenes respectively as major products.
One-Electron Chemical Reductions of Phenylalkylsulfonium Salts
Beak, Peter,Sullivan, Thomas A.
, p. 4450 - 4457 (2007/10/02)
Twenty-two arylalkylsulfonium salts have been reduced with potassium in graphite in tetrahydrofuran and the sulfide products identified.Two trialkylsulfonium salts did not reduce under these conditions.Comparison of the sulfides from a series of monophenylalkylsulfonium salts reveals a leaving-group propensity of benzyl > secondary > primary > methyl > phenyl in a ratio of 28:(6.0 +/- 0.3):1.0:(0.53 +/- 0.09): 0.05.The cleavage ratio is shown to be independent of the electron source and the homogeneity of heterogeneity of the reaction in two cases.Multiplicative transitivity of the above ratios is not observed, although the same qualitative order is found for other comparisons.These results are interpreted in terms of the initial formation of a ?-ligand radical anion sulfonium cation, which undergoes cleavage to a carbon radical and a sulfide.This appears to be the first evidence for this type of structure in a sulfur system.Leaving-group propensities different from the above order are observed in reductions of diphenylsulfonium and benzo-fused sulfonium salts, and rationales are offered.The intermediates in these reactions appear to be different from those involved in radical additions to, or displacements on, sulfur.
