Synthesis of 2‐Azabicyclo[m.n.0]–Alkanes and Their Application towards the Synthesis of Strychnos and Stemona Classes of Alkaloids

2‐Azabicyclo[m.n.0]alkane ring systems, the conceptual precursors towards the synthesis of Strychnos and Stemona classes of alkaloids, were synthesized from tert‐butyl 2‐(phenylsulfonyl)‐7‐aza‐bicyclo[2.2.1]hept‐2‐ene‐7‐carboxylate by alkyl Grignard reaction and intramolecular cyclisation of the in situ generated ring opening product 2. The synthesized cis‐hexahydroindole 3 and cis‐octahydro‐benzo[b]azepine 5 scaffolds were utilized to construct the advanced intermediates 25 and 35, respectively, towards the synthesis of the corresponding Strychnos and Stemona classes of alkaloids. From a common precursor to three 2‐azabicyclic ring systems: This is a first report on the synthesis of cis‐hexahydroindole, cis‐octahydroquinoline and cis‐octahydrobenzo[b]azepine scaffolds using a common synthetic route and a common precursor. The scaffolds were diversified into more advanced scaffolds towards the synthesis of Strychnos and Stemona class of alkaloids.