65564-83-2Relevant articles and documents
A synthesis of ynolates via the cleavage of ester dianions
Shindo, Mitsuru
, p. 4433 - 4436 (1997)
A new method for ynolate synthesis via the cleavage of ester dianions has been developed. The key intermediates, ester dianions, generated from α-bromocarboxylic acid ester enolates via lithium-halogen exchange turned out to be so labile that they were cleaved rapidly to give ynolates.
H-*BEA Zeolite-Catalyzed Nucleophilic Substitution in Allyl Alcohols Using Sulfonamides, Amides, and Anilines
Aoki, Shunsuke,Fujii, Takeshi,Morita, Sachiko,Nishida, Ryo,Ohtsuki, Akimichi,Okumura, Kazu
, (2020/07/24)
Herein, we report a novel zeolite-catalyzed nucleophilic substitution in allyl alcohols. The product yield was improved upon the addition of NaOTf (0.05 mol-percent) using the studied zeolites. The highest yields were observed using H-*BEA(Si/Al2 = 40)/NaOTf. The scope of the reaction with respect to the nucleophile was examined using 1,3-diphenylprop-2-ene-1-ol as a model substrate under optimized reaction conditions. p-Substituted aryl sulfonamides bearing electron-rich or electron-deficient substituents, alkyl sulfonamides, and heteroaryl sulfonamides undergo the amidation reaction to produce their corresponding allyl sulfonamides in good yield. Amides and anilines exhibited low activity under the optimized conditions, however, performing the reaction at 90 °C produced the target product. The scope of the allyl alcohol was investigated using p-toluenesulfonamide as the nucleophile and the reaction proceeded with a variety of allylic alcohols. To probe the practical utility of the H-*BEA-catalyzed amidation reaction, a gram-scale reaction was performed using 1.01 g (4.8 mmol) of allyl alcohol, which afforded the target product in 88 percent yield.
Investigation of substituent effects on the selectivity of 4π-electrocyclization of 1,3-diarylallylic cations for the formation of highly substituted indenes
Smith, Chris D.,Rosocha, Gregory,Mui, Leo,Batey, Robert A.
supporting information; experimental part, p. 4716 - 4727 (2010/09/05)
(Figure Presented) Differentially substituted 1,3-diaryl-substituted allylic cations generated by ionization of the corresponding allylic alcohols in the presence of a Lewis acid undergo chemoselective and regioselective electrocyclization reactions to generate 1-aryl-1H-indenes. Electrocyclization only occurs for allylic cations bearing a 2-substituent, with 2-ester and 2-alkyl substituents both tolerated. In general, the presence of electron-withdrawing substituents deactivates the ring and disfavors cyclization. In contrast, the selectivity of cyclization of systems containing electron-donating substituents depends on the nature and position of the electron-donating group. Electron-donating substituents at the meta position particularly favor cyclization. There was no obvious correlation of cyclization selectivity with calculated electron densities as has been suggested for electrophilic aromatic substitution reactions. However, the calculated selectivities determined by a gas-phase (B3LYP/6-31G* + ZPVE) comparison of the relative rates of cyclization were in remarkably good agreement with the observed selectivities. Calculated transition-state structures for cyclization are consistent with a cationic π4a conrotatory electrocyclization mechanism. In some cases involving more electron-deficient systems, the initially formed 1H-indene underwent subsequent alkene isomerization to the 3H-indene. In one example, an unusual dimerization reaction occurred to give a cyclopenta[a]indene via an unusual formal cationic 2π+2π cycloaddition of the allylic cation with the intermediate indene.
