Acetoxy radicals, cage reactions

It is clear (23) that three products result from reactions of acetoxy radical pairs within the solvent cage acetyl peroxide (estimated at 38% ), methyl acetate (12.4% ), and ethane (2.9% ). The implied near equality of rates for decarboxylation of the acetoxy radicals and diffusion from the cage has been given quantitative expression in work of Braun, Rajben-bach, and Eirich (2). These workers studied the variation in the amounts of ethane and methyl acetate formed from acetyl peroxide as a function of solvent viscosity, and they derived a rate constant for the decarboxylation of acetoxy radical at 60°C. of 1.6 X 109 sec."1. 

To explain the high chemical yield in the transformation A - D, coupled with the fact that the quantum yield for the photodecomposition of nitrites is less than unity, it was suggested that the Barton reaction might take place through a radical "cage mechanism.2 However, recent studies at the Institute on the mechanism of nitrite photolysis have shown this not to be so. Photolysis of an equimolecular mixture of 3/3-acetoxy-androstan-6/8-yl nitrite (102) and 3/8-acetoxy-cholestan-6/8-yf nitrite containing 98% of nitrogen as N16 (103) in iso-octane or toluene... 

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