Electroreductive cyclization occurs when A = B = CO 2 Me and CN, but not when A = CO 2 Me or CN and B = H; reasons for this behavior are presented. Cyclization proceeds stereoselectively when the supporting electrolyte is LiClO 4 or Mg(ClO 4 ) 2 , but not when n-Bu 4 NBr is used. Chelation between the substrate and the metal is suggested to account for the result. ... (b) S. Patai, Z. Rappoport (Eds.), The Chemistry of EnonesWiley, New York (1989) Chapter 14.