Synthesis along biosynthetic pathways. Part 2. Synthesis of protostephanine
Abstract
The dienone protostephanone (3) is synthesised by phenol coupling or by Pschorr cyclisation from readily prepared tetrahydroisoquinolines, and the corresponding dienols (17) and (18) are converted by rearrangement, fragmentation, and reduction into protostephanine (4). This sequence mimics the natural pathway to the alkaloid.