Furo[3',4':6,7]naphtho[2,3-d]-1,3-dioxol-6(8H)-one,5,5a,8a,9-tetrahydro-5-(4-hydroxy-3,5-dimethoxyphenyl)-9-[(phenylmethyl)amino]-, [5R-(5a,5ab,8aa,9b)]-