Radical β-fragmentation of bicyclo[3.3.0]-carbinolamides: Synthesis of five- and eight-membered cyclic imides

16 pages, 1 figure, 1 table, 2 schemes.The influence of 4-alkyl or 4-aryl substituents in the regioselectivity of the β-fragmentation of carbinolamidyl radicals generated from the corresponding carbinolamides (7-13) by irradiation with visible light in the presence of (diacetoxyiodo)benzene and iodine is described. In the case of the less hindered carbinolamides 1-hydroxyazabicyclo[3.3.0]octan-3-one (7) and 4-(2'-phenylethyl)-1-hydroxyazabicyclo[3.3.0]octan-3-one (8) important amounts of 8-membered cyclic imides were obtained together with the expected 5-membered imides (succinimides).This work was supported by the Investigation Programme nº PB93-0171 of the Dirección General de Investigación Científica y Técnica