The gross structure and precise stereochemistry of 'tribromothujone' have been identified; its adjacent bromine atoms are cis-orientated. The mechanism of its formation is discussed. A number of halogenated compounds derived from ( + ) -thujone have been obtained and their absolute configurations determined. ( -) -Carvotanacetone dibromide and two tribromides have been stereochemically identified.

The known bromination of thujone (I) with Br2 gives a racemic tribromide, whose gross structure and precise stereochemistry (II) are determined.