Oxidation of Organocuprates with o-Dinitrobenzene: 'Higher Order' Cyanocuprates are Different.

Mixed organocuprates, RR'CuLi are oxidized by nitroarenes to a mixture of RR, RR', and R'R'. The ratio of products provides information about the structure of the cuprate under consideration and exchange processes that may occur. For example, oxidation of BuPeCu(CN)Li(2) (BuPeCuLi prepared from CuCN) with o-dinitrobenzene yields a 1:4:1 ratio of octane, nonane, and decane, respectively, which is consistent with a dimer but not with the monomer, trimer or tetramer. Intermolecular exchange, if it exists, must be slow; otherwise, the ratio of products would be 1:2:1.