Samarium Diiodide Mediated Ketyl-Aryl Coupling Reactions - Influence of Substituents and Trapping Experiments
作者:Ulrike K. Wefelscheid、Mathias Berndt、Hans-Ulrich Reißig
DOI:10.1002/ejoc.200800293
日期:2008.7
derivatives as single diastereoisomers in most cases. The position of the substituents was also of crucial influence on the outcome; in several cases ipso-substitution leading to the formation of spiro compounds was observed. Electron-donating substituents at the aromatic moiety are less favourable for the ketyl–aryl couplings. They apparently impede the second electron transfer that is involved in this multi-step
La reduction electrochimique de derives de l'aryl-5 pentanone-2 conduit a des derives de l'(hexahydro-1,2,3,4,6,8a methyl-1) naphtol-1
La 还原电化学 de 衍生 de l'aryl-5 pentanone-2 导管 a des 衍生 de l'(hexahydro-1,2,3,4,6,8amethyl-1)naphtol-1
Electroreductive intramolecular coupling of nonconjugated aromatic ketones
作者:Naoki Kise、Takeshi Suzumoto、Tatsuya Shono
DOI:10.1021/jo00085a033
日期:1994.3
The electroreduction of nonconjugated aromatic ketones gave intramolecularly coupled products. The best result was obtained using an Sn cathode in i-PrOH containing tetraalkylammonium salt as a supporting electrolyte. This reductive cyclization proceeded with remarkable stereoselectivity, and the cis isomer was obtained exclusively. A variety of new bi- and polycyclic compounds were synthesized. The reaction mechanism was studied, and it was suggested that the anion radical generated by one-electron transfer to a carbonyl group attacks an aromatic ring intramolecularly. The choice of counter cation of the anion radical was critical for the reductive cyclization. Other reductive methods employing metal reducing agents were also studied. Reduction with Na in HMPA-THF gave the same cyclized product, though the yield was lower than that with the electroreduction.