Rates of decarboxylation of acyloxy radicals formed in the photocleavage of substituted 1-naphthylmethyl alkanoates

Article abstract of DOI:10.1021/ja00007a049

Rates of decarboxylation (k_CO2^R) have been estimated for the acyloxy racicals 7a-f formed in the photolysis of substituted 1-naphthylmethyl 6a-f. These rates are on a mechanism involving initial carbon-oxygen homolytic bond cleavage from the excited singlet state. The products are formed by two competing pathways: electron transfer in the radical pair to give an ion pair and decarboxylation. Measured product yields along with an of the electron-transfer rate (k_ET) allow calculation of k_CO2^R as a function of R. The values obtained are the following (R, k (10⁹ s^-1)): CH₃, < 1.3; CH₃CH₂, 2.0; (CH₃)₂CH, 6.5; (CH₃)₃C, 11; PhCH₂, 5.0; PhCH₂CH₂, 2.3.