Rearrangement of 2-azanorbornenes to tetrahydrocyclopenta[c]pyridines under the action of activated alkynes – A short pathway for construction of the altemicidin core

•Amino-Claisen rearrangement of azabicyclo[2.2.1]heptenes under the action of alkynes.•Diastereoselective pathway to altemicidin and dinklageine core analogs.•Effective synthesis of 2,4a,7,7a-tetrahydrocyclopenta[c]pyridines under mild conditions.•Short pathway for construction of the altemicidin core.