Organic Syntheses by Free Radical Reactions,

Radical thermochemistry and organic reactions*

Most free radicals are transient species and it is therefore difficult to measure their thermochemical properties. We have used two new techniques that address this problem. Photoacoustic calorimetry was used to measureheats of formation of free radicals and thus homolytic bond strengths, while photomodulated voltammetry was used to measure their oxidation and reduction potentials. The data off...

Organic Peroxides in Radical Synthesis Reactions

Physiological aspects of free-radical reactions.

Enzymes which catalyze the formation of free radicals in vitro will catalyze similar reactions in vivo. We believe that the formation of some kinds of free radicals has definite physiological meanings in metabolism. In this sense, the enzymes forming such free radicals are concluded to be in evolutionally advanced states. Elaborated structure and function of enzymes such as horseradish peroxida...

Kinetic Studies of Some Free Radical Reactions

Kinetic and mechanistic studies on some characteristic freeradica1 reactions are reviewed briefly. The unimolecular rearrangements: RCMe2CH ÷ Me2CCH2R, fall into two classes. Class 1: R = R'C(O)O for which the 1,2—migration occurs via a 5—eenter cyclic transition state with considerable charge separation, [R'C02 Me2CCH2]*. Class 2: R = H2C=CH, Me3CC=0, C6H5, Me3CCsC, and CsN, for which migratio...

The free-radical chemistry of polyethylene glycol: organic reactions in compressed carbon dioxide.

The thermal oxidative degradation of polyethylene glycol (PEG) is known to occur in an oxygen atmosphere at elevated temperatures. In this study, PEG radicals assumed to result from thermal oxidative degradation are successfully applied, in combination with compressed CO(2), to initiate a range of free-radical reactions, such as selective formylation of primary and secondary aliphatic alcohols,...