| Research Abstract |
In this study, we have presented electroreductive one-pot double vicinal C-acylation of α-substituted acrylates and styrenes in the presence of acid anhydrides or N-acyl imidazoles in N,N-dimethylformamide (DMF) containing tetrabutylammoniun bromide as a supporting electrolyte using an undivided cell equipped with Zn plates as the anode and the cathode. Furthermore, treatment of anthracenes, acenaphthalenes, and acrylic acid esters in the presence of acid chlorides with Mg turnings for Grignard reaction without any pie-treatment, in DMF at room temperature brought about regioselective and efficient one-pot double C-acylation to give the corresponding 9,10-diacylated anthracenes, 1,2-diacylated acenaphthalenes, and 2-carboalkoxy-1,4-diketones, respectively, in moderate to good yields. Use of α,ω-dicarboxylic acid chlorides instead of mono-functional ones including succinyl chloride, glutaryl those containing hetero atoms in their carbon chain as acylating agents in this reaction led to unique and selective formation of intermolecular tandem cycloaddition products, whose structures were characterized by usual spectroscopic methods(^1H-,^<13>C-NMR, IR, MASS), elemental analysis and single crystal X-ray fraction. These reactions may be initiated by electron transfer from an electrode or Mg-metal to activated olefins and aromatic rings to generate the corresponding anion radicals which are subjected to electrophilic attack of acylating agents, followed by the second electron transfer. The resulting anion intermediates may be again attacked by acylated agents, forming the double C-acylated products.
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