Intramolecular reactions involving reactive species (e.g., acylnitrene and oxocarbene) have been applied to effect substitution at non-activated methylene-groups to obtain 1,2-difunctionalised adamantanes. The syntheses of tetrahydroadamantano[2,1-d]pyrimidin-2-one, a number of 2H-adamantano[1,2-e]pyridazin-3(4H)-ones, and their fully reduced derivatives are also reported.