5H-4a,7-Ethano-4H-cyclohepta(1,2-b:4,5-c')difuran-2,11(3H)-dione, hexahydro-8-methyl-3-methylene-, (3aR,4aS,7R,7aS,8R,9aR)- 5H-4a,7-Ethano-4H-cyclohepta(1,2-b:4,5-c')difuran-2,11(3H)-dione, hexahydro-8-methyl-3-methylene-, (3aR-(3aalpha,4aalpha,7alpha,7aalpha,8alpha,9aalpha))- 61490-63-9 Microhelenin A Microhelenins