 It is a bicyclic molecule and has two bridgehead chiral carbons between the five-membered ring and the six-membered ring (highlighted in green in the figure below).Because of its structure and bioactivity, mesembrine has been a target for total synthesis over the past 40 years.Over 40 total syntheses have been reported for mesembrine, most of which focused on different approaches and strategies for the construction of the bicyclic ring system and the quaternary carbon.