Synthesis of 3-alkoxy-3-aryl-4,4-diisopropyl-1,2-dioxetanes and their base-induced chemiluminescence

Low-temperature singlet oxygenation of 1-alkoxy-1-aryl-2,2-diisopropylethyl enes (9) gives the corresponding 1,2-dioxetanes (10) in high selectivity. D ioxetanes (10) are thermally stable enough to permit handling at room tempe rature, though an alkoxy group affects significantly their thermal stabilit y and the order of half-life is MeO < EtO < i-PrO >> tert-BuO. On treatment with tetrabutylammonium fluoride in DMSO, dioxetanes (10e - 10h) bearing a m-siloxyphenyl decompose rapidly to emit intense blue light with (CL)-C-Ph i > 0.2. For the base-induced decomposition of 10e - 10h, the order of rate of decomposition is MeO < EtO < i-PrO < tert-BuO. (C) 1999 Elsevier Scienc e Ltd. All rights reserved.