(4aS,8aS)-octahydropyrano[3,2-b]pyran InChI=1/C8H14O2/c1-3-7-8(9-5-1)4-2-6-10-7/h7-8H,1-6H2/t7-,8-/m0/s pyrano[3,2-b]pyran, octahydro-, (4aS,8aS)-