9-oxabicyclo[3.3.1]nona-2,6-diene. Short access and allylic bromination

9-Oxabicyclo[3.3.1]nona-2, 6-diene (3) has been synthesized from cycloocta-1, 5-diene in two steps in an overall yield of 88%. The dihedral-angle dependence of its 1 H solution NMR data and the double signal set of its 1 3 C CP MAS NMR spectrum correspond to the results of the single crystal structure analysis. Reaction of 3 with N-bromosuccinimide in the presence of sodium peroxodisulfate or benzoylperoxide has led in good yield to a dibromo derivative 4, and a tribromo derivative 5, respectively. Compounds 4 and 5 feature two allylic bromine substituents, while an additional vinylic bromine atom is present in 5. According to a single crystal structure study the lattice of 4 consists of pairs of enantiomers similar to those found in the case of 3.