Abstract The one‐bond nucleophilic reactivities of seven cyclic α‐diazo carbonyl compounds in dichloromethane were determined by analyzing the kinetics their reactions with benzhydrylium ions (one‐bond reference electrophiles) at 20 °C according to Mayr‐Patz equation. Though not calibrated for pericyclic reactions, identified nucleophilicities also reflect relative 1,3‐dipolar cycloadditions di...