Synthesis of a compound having the essential structural unit for the hetisine-type of aconite alkaloids

A hexacyclic compound 1, which carries an almost full structure of the hetisine skeleton lacking only the six-membered ring with an exo methylene group, was synthesized by applying an acetal-ene reaction on 5 for the bond formation of C-14 and C-20 as well as stereoselective hydrocyanation reaction on 7 for construction of the azabicyclo ring system.