SUBSTITUENT EFFECTS ON THE RATE OF CARBENE FORMATION BY THE PYROLYSIS OF RIGID ARYL SUBSTITUTED DIAZOMETHANES

Article abstract of DOI:10.1016/S0040-4020(01)96390-2

Rate constants for the pyrolysis of 1-diazo-4,4-dimethyl-1,4-dihydronaphtalenes, 4a-4e, have been measured in methanol:6percent triethylamine.In contrast to non-rigid cases, like diphenyldiazomethanes, where all para substituents show a rate increase compared to hydrogen, these rates show a linear Hammett correlation for all para substituents with ?⁺ = -0.84.This observation is rationalized by a non-linear process for loss of nitrogen leading directly to the ground-state singlet of the carbene, 17.This carbene is then trapped to give ether 11.