Download PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... A simple and efficient synthesis of (±)-mesembrine 1 is described employing double Michael addition and as the key step in 18% overall yield. ... Reagents and conditions: (a) 10% aq NaOH, TBAHSO4, 0°C, 30min, 76%; (b) NaH, ... Reagents and conditions: (a) 10% aq NaOH, ...