Photolysis of Methylene Iodide in the Presence of Olefins

Spin–Orbit Ab Initio Investigation of the Photolysis of Bromoiodomethane

“…[3] Second, their functions in organic synthesis: ultraviolet photoexcitation of diiodomethane in solution has long been used for cyclopropanation of alkenes. [4][5][6][7] Third, studies of small polyhalomethanes are helpful for the understanding of fundamental photochemical reaction mechanisms following laser excitation. Herein, the research object bromoiodomethane (CH 2 BrI), with two different carbon-halogen bonds, is an excellent model for investigating selective bond dissociations upon electronic excitation.…”

Thermal decomposition studies of ω-iodoacyl peroxides

“…T o explain our results, steps [5] and [6] would also be necessary and competitive with step [3] (RH represents any convenient source of CH bonds). For 5-iodovaleryl peroxide (n = 4) these steps are a reasonable possibility, a t least to some extent, but for the higher peroxides (n = 5 and l o ) , step [4] would have to be assumed to be replaced completely by steps [5] and [6] since no lactone is formed.…”

“…The peroxides decomposed smoothly over a period of a few hours for solutions usually 0.1-0.7 M, but were found, in every case, to give product mixtures more complex than that obtained in the vapor-phase pyrolysis of 4-iodobutyryl peroxide (6). No iodine was produced and no olefin was found, although the iodine and ethylene produced by solution decomposition of 3-iodopropionyl peroxide (5) are probably analogous to our production of I(CHZ),I, where, for n = 2, the 1,2-diiodoethane would be unstable.…”

“…Although the thermal decomposition of diacyl peroxides has been studied extensively (1-4) because of its importance as a source of free-radical intermediates, whaloacyl peroxides have received comparatively little attention (5,6). Leffler and West ( 5 ) showed that 3-iodopropionyl peroxide decomposed in benzene to give a mixture of 2-icdoethyl 3-iodopropionate, ethylene,.…”

“…Thus I(CH2),' probably abstracts iodine from reaction products as well as the peroxide (step [3]). Also, although the formation of I (CH2) 2, I is most simply explained by the coupling of two I(CH2),' radicals (step [6]), a t least two other possibilities exist (steps [6'] and [6"] Step [2'] is unusual in that i t involves a radical displacement on carbon. An 2A referee has indicated surprise a t the lack of esters I(CHZ),COO(CHZ),I among the products.…”