Electrochemical reductive alkylation of (benzophenone)Cr(CO) 3 and (benzophenone)[Cr(CO) 3] 2

Abstract

The electrochemical reduction of (benzophenone)Cr(CO) 3 and (benzophenone)[Cr(CO) 3] 2 in hthe presence of a series of alkyl chlorides which are more difficult to reduce, has been carried out in N,N-dimethylformamide on a mercury pool cathode. When methyl chloride and p-cyanobenzyl chloride are used as alkylating agents, complexed monoalkylated ethers are exclusively obtained as substitution products, in yields ranging from 36 to 54%. Complexed alkylated alcohols aer isolated as the major products when (benzophenone)Cr(CO) 3 is reduced in the presence of benzyl-chloride and its 2,3,5-trimethyl derivative, in 48 and 44% yields, respectively. These last results suggest the intermediate formation of a charge transfer complex between the aromatic ring of the electrophile and the complexed ketone.