Abstract: | Reported herein is an exceptional chemoselective ring‐opening/C(sp3)−C(sp3) bond formation in the copper(I)‐catalyzed reaction of cyclopropanols with diazo esters. The conventional O−H insertion product is essentially suppressed by judicious choice of reaction conditions. DFT calculations provide insights into the reaction mechanism and the rationale for this unusual chemoselectivity. |