InChI=1/C14H22O6/c1-13(2,3)19-10(15)9(12-17-7-8-18-12)11(16)20-14(4,5)6/h7-8H2,1-6H di-tert-butyl 1,3-dioxolan-2-ylidenemalonate propanedioic acid, 1,3-dioxolan-2-ylidene-, bis(1,1-dimethylethyl) ester