for the following products
(3R,3aR,4S,4aR,7R,8aR,9aR)-7-[(Ethoxycarbonyl)amino]dodecahydro-3-methyl-1-oxo-naphtho[2,3-c]furan-4-carboxylic acid and (1R,3aR,4aR,8aR,9S,9aR)-1-methyl-3-oxodecahydro-3H-spiro[naphtho[2,3-c]furan-6,2'-[1,3]dioxolane]-9-carboxylic acid