Free Radical Reactions of Aldehydes

The reactions of alkyl radicals. Part 1.—n-Propyl radicals from the photolysis of n-butyraldehyde

“…THE DISPROPORTIONATION OF I~-PROPYL RADICALS (2).-Nine runs that provide direct information on k2 were carried out between 25" and 191°C with mean aldehyde concentrations between 0.5 and 1.8 pmole an-3. The number of radicals disproportionating was taken as equal to twice the quantity of propylene found at the end of the run.…”

Chemistry of Acyl Radicals

“…Homolytic substitution reactions were among the first reactions of acyl radicals to be reported. Thus, as long ago as 1947, Winstein and Seubold reported the formation of acyl chlorides on refluxing of aldehydes in tetrachloromethane with initiation by benzoyl peroxide (Scheme ) . A simple chain process is involved in which the acyl radical abstracts chlorine from the solvent, the homolytic substitution step, and the ensuing trichloromethyl radical carries the chain by hydrogen-atom abstraction from further aldehyde (Scheme ).…”

Metal‐free Photochemical Atom Transfer Radical Addition (ATRA) of BrCCl3 to Alkenes

“…Upon irradiation, phenylglyoxylic acid is excited to its singlet and triplet state which can then lead to its decomposition to benzoyl radical ( I ) [28,29] . In the presence of bromotrichloromethane, the benzoyl radical ( I ) can abstract the bromine atom furnishing benzoyl bromide ( II ) and trichloromethyl radical ( III ) via a halogen atom transfer (XAT) [34] . The latter radical can then react with an electron‐rich double bond leading to radical ( IV ), which reacts with another molecule of bromotrichloromethane, leading to product 2 a and trichloromethyl radical ( III ), which takes part in a radical propagation chain process, which is supported by the quantum yield calculated [Φ>1] [29] .…”