Reactions of dibromocyclopropane 2a, containing two spiro-fused 1, 3-dioxane rings, with MeLi gave only the methylation products 8 and 9 even at elevated temperatures. In contrast, the cyclohexane analogue 2b treated with MeLi underwent a smooth rearrangement to bicyclo [1.1. 0] butane 11b at− 78,− 10, or+ 35° C. Treatment of 2a with PhLi gave the α-Ph anion 13 as the only product, which underwent smooth methylation with MeI to give 14. ...