THE REACTIVITY OF THE ELECTROGENERATED CYANOISOPROPYL ANION (CBARME2CN) VERSUS SN2 AND ACID-BASE REACTIONS

The electrochem. redn. of Me2CBrCN to give Me2C(CN)- (I) was studied in the presence of Br(CH2)nCN (n = 2, 3, 4) (II-IV, resp.). I reacted with II and III either as a base to give H2C:CHCN and cyclopropanenitrile, resp., or as a nucleophile to give NCCMe2(CH2)nCN (n = 2, 3). I was unreactive towards IV. Thus, the reported eliminations are not controlled by the acidity of the substrate, i.e. by cleavage of the C-H bond under attack by I. These eliminations require the possible concerted cleavage of the C-H and C-Br bonds and are thus affected by the relative positions of these bonds.