Preparative flash vacuum thermolysis. Formation of 3-noradamantylacetylene via adamantylidenecarbene

3-Ethynyltricyclo[3.3.1.03,7]nonane is conveniently prepared from adamantanone, via an anomalous alkylidenecarbene rearrangement, by flash vacuum thermolysis of 5-adamantylidene-2,2-dimethyl-1,3-dioxane-4,6-dione.