Convenient preparation of aryl-substituted nortropanes by SuzukiMiyaura methodology

The synthesis of a new bicyclic vinyl boronate (5) was accomplished from N-Boc-nortropinone (6) in two steps. The Suzuki–Miyaura coupling of 5 to a variety of aryl bromides and triflates afforded 3-aryl-8-azabicyclo[3.2.1]oct-2-enes in good yields by adjusting the substrate and (or) reaction conditions. Reduction to the 3-aryl-8-azabicyclo[3.2.1]octanes was achieved by hydrogenation. Interestingly, the coupling was also successful with benzyl bromides, providing entry into another group of intermediates.Key words: nortropane, Suzuki–Miyaura, boronate, piperidine, GPCR, benzyl bromide.