The 1-Scission Process

This process is very fast with = 1, and has been observed in the photolysis of nitrite esters X = NO and the oxidation of cyclopropanols, with a regiochemistry of ring opening which has been compared in terms of frontier molecular orbital theory to the one observed with cyclopropylcarbinyl radicals (Section V.2.B). It is also a fast process with n = 2 as in the oxidation of cyclobutanols, although photolysis of a steroidal cyclobutyl nitrite gives the cyclobutanol in substantial amounts (unexpected), along with products resulting from the )5-scission of the cyclobutanoxyl radical to tertiary and also 

This very brief and incomplete summary of the literature shows that the opening process is very effective and may be observed under a variety of conditions. We now comment on the few cases where free radical intramolecular addition has been proposed. 

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