Thermolysis of Vinyldiazomethanes as a Method for the Generation of Vinylcarbenes and a Comparison with Cyclopropene Photochemistry

Article abstract of DOI:10.1021/jo00140a023

The pyrolysis of the vinyldiazomethanes 6 (X = H), 8, 9, and 10 gives mixtures of 3H-pyrazoles and cyclopropenes.The kinetics and product distribution for each case lead to a determination of the rate of vinylcarbene formation and, therefore, a direct determination of the relative carbene stabilities.The conclusion is that carbene 14 is more stable than 15.These results are then used as a basis for a discussion of the carbenes generated from the singlet photochemistry of unsymmetrical cyclopropenes, 11.