Electroreductive intramolecular coupling of aromatic δ- and ε-keto esters
Electroreduction of aromatic δ- and ε-keto esters in the presence of chlorotrimethylsilane and triethylamine gave five- and six-membered cyclized products. The products were transformed to the corresponding α-hydroxy ketones.
Electroreductive acylation of aromatic ketones with acylimidazoles
The intermolecular reductive coupling of aromatic ketones with acylimidazoles was effected by electroreduction in the presence of chlorotrimethylsilane and gave α-trimethylsiloxy ketones and esters. The best result was obtained using Bu4NPF6 as a supporting electrolyte and a Pb cathode in THF. The α-trimethylsiloxy-containing products were transformed to the corresponding α-hydroxy ketones and esters by treatment with TBAF in THF. This method was also effective for the intramolecular reductive coupling of δ- and ε-keto acylimidazoles.