Planta Med 2016; 82 - PC6
DOI: 10.1055/s-0036-1578708

Synthetic Studies Towards (-) Mesembrine

MA Albadry 1, 2, SC Rotte 2, PB Lasonkar 2, AG Chittiboyina 2, IA Khan 1, 2
  • 1Departments of BioMolecular Sciences, Division of Pharmacognosy
  • 2National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS 38677, USA

Mesembrine is a naturally occurring alkaloid which has been isolated from Sceletium tortosum, family Aizoaceae. It has a therapeutic value in the treatment of depression as selective serotonin reuptake inhibitor. Because of its challenging chemical features such as a cis-3a-aryloctahydroindole moiety with syn configuration at two bridge-head stereogenic centers. [1] Several synthetic studies have been published to control the construction of the sterically hindered, benzylic quaternary stereogenic center at C-3a. [2] By utilizing Michael addition on chiral enolate derived from benzyl oxazoline, the desired stereogenic center at carbon 3a was created early in the synthesis followed by carbene insertion and intramolecular aldol reactions to complete the aryloctahydroindole scaffold. The complete details of synthetic transformations will be discussed.

Fig. 1

Acknowledgements: This research is supported in part by The United States Department of Agriculture, Agricultural Research Service, Specific Cooperative Agreement No. 58 – 6408 – 1-603 – 07

References:

[1] K. Geoghegan, P. Evans, The Journal of Organic Chemistry 2013, 78, 3410 – 3415.;

[2a] D. F. Taber, T. D. Neubert, The Journal of Organic Chemistry 2001, 66, 143 – 147;

[2b] S. P. Chavan, D. A. Khobragade, A. B. Pathak, U. R. Kalkote, Tetrahedron Letters 2004, 45, 5263 – 5265.