Synthesis of bis-cycloalkanes^a.

^aReaction conditions: 1 (7 mol%, with respect to 2f), 2f (0.25 mmol), 1,4-butanediol/1,5-pentanediol (1.5 mmol), KO^tBu (1 mmol), toluene (5 mL), 135 °C, 24 h (isolated yield).