Gravar-mail: Crystal structures of 3,6-di­allyl­tetra­cyclo[6.3.0.0(4,11).0(5,9)]undeca-2,7-dione and 1,7-di­allyl­penta­cyclo­[5.4.0.0(2,6). 0(3,10).0(5,9)]undecane-8,11-dione: allyl­ated caged compounds