1-Naphthylcarbene: Spectroscopy, Kinetics, and Mechanisms

Article abstract of DOI:10.1021/ja00274a013

The reactions of 1-naphthylcarbene have been examined by using laser flash photolysis techniques.Generation of the carbene from the diazo precursor in hydrocarbon solvents leads to the formation of 1-naphthylmethyl radicals, which were characterized by their absorption at 363 nm.However, product studies in cyclohexane and cyclohexane-d₁₂ reveal that the main reaction path is carbene insertion into the C-H bond rather than H abstraction. 1-Naphthylcarbene reacts readily with nitriles to yield nitrile ylides which can also be generated from the corresponding azirine.For example, the carbene reacts with acetonitrile with a rate constant of 4.6 X 1E5 M^-1s^-1 at 300 K to yield an ylide that can be trapped readily with electron-deficient olefins, such as diethyl fumarate.Reaction of the carbene with oxygen (k = 3.5 X 1E9 M^-1 s^-1) yields the carbonyl oxide (λ_max 435 nm).Other reactions examined include halogen abstraction, addition to ketones, and reactions with triethylamine, pyridine, and ethers.The absolute kinetics of the various reactions were examined by monitoring the formation of the products (e.g., ylides, radicals, etc.), since the carbene spectrum was not detected directly.