(1S,8S,12S,2R,5R,6R,9R)-8-(3a,6a-Dihydro-4H,6H,3aH,6aH-oxolano[3,4-d]isoxazol-3-yl)-1-formyl-5-methyl-10-(methylethyl)tetracyclo[7.4.0.0<2,6