US10287296B2 - Process for the Preparation of (s)-2-((4R,4aS,6R,7R,7aR,12bS)-7,9-Dimethoxy-1,2,3,4,5,6,7,7a-Octahydro-4a,7-Ethano-4,12-Methanobenzofuro[3,2-E]isoquinolin-6-Yl)-3,3-Dimethylbutan-2-Ol