Fig. 2: Substrate expansion by varying substitution (R¹ and R²) at 4πe-system (a, b, g).

(a) Reactions were carried out at rt with 0.1 mmol of substrate in 1.0 mL CHCl₃. (b) Isolated yields. (c) Reaction with 0.05 equiv In(SbF). (d) The ratio determined by ¹H-NMR. (e) 2n:R¹ = Me, R² = OMe. (f) Reaction at 50 °C. (g) Unless noted, dr > 20:1.