作者:Michael A. Kinder、Lars Meyer、Paul Margaretha
DOI:10.1002/1522-2675(20010815)84:8<2373::aid-hlca2373>3.0.co;2-4
日期:2001.8.15
On irradiation in the presence of tetrachloroethene (TCE), both isocoumarins 3 and isothiocoumarins 4 afford in high yields the cis-fused cycloadducts 8 and 9, while only the oxacycles 3 undergo photocycloaddition to 2,3-dimethylbut-2-ene (TME) to give mixtures of cis- and trans-fused products 10 and 11, respectively, in moderate yields. This higher efficiency in reacting with TCE as compared to TME for compounds 3 and 4 contrasts the behavior of simple cyclic enones, e.g., 5,5-dimethylcyclohex-2-enone (12), which is converted to bicyclooctanones about fifty times faster with TME than with TCE.