The synthesis of spiro[adamantane‐[1,2]dioxetanes]

It is shown that the spiroadamantane group stabilizes thermally labile 1,2‐dioxetanes sufficiently to permit isolation. With the help of this stabilizing group it was possible to prepare the first sulfur substituted dioxetanes 9k and 1 and characterize them by low temperature 13C and 1 NMR spectra. Photosensitized singlet oxygenation at low temperature, using either polymer‐bound Rose Bengal or tetraphenylporphyrin as sensitizer in methylene chloride, of the corresponding 2‐methyleneadamantanes 8 was the method of choice for the preparation of the spiro[adamantane‐[1,2]dioxetanes] 9, provided that the methylene carbon bears no alkyl or phenyl substituents. The Kopecky method, i.e. hydroperoxybromination of the 2‐methyleneadamantanes 8 and subsequent dehydrobromination, proved unsuccessful to prepare the dioxetanes 9.