1. The total synthesis of (-)-cyanthiwigin F by means of double catalytic enantioselective alkylation J.A. Enquist, Jr., B.M. Stoltz, Nature 2008,453,1228 Presented by Vijayarajan Devannah on 5/7/2013

2. About Professor Brain M. Stoltz Education and Professional Experience B.S., Indiana University of Pennsylvania 1993 Ph.D., Yale University (John Wood) 1997 NIH posdoctoral Fellow, Harvard University ( E. J. Corey ) 1998-2000 Currently professor of chemistry at California Institute of Technology, Pasadena. Honors and Awards Camille and Henry Dreyfus New Faculty Award, 2000 Glaxosmithkline Chemistry scholar Award 2002 and 2003 Amgen Young investigator Award 2003 Arthur C Cope Scholar Award from the American Chemical Society 2005 E J Corey Award for outstanding original contribution in the organic synthesis by a young investigator, 2009 H.C. Brown Lecturer in Organic Chemistry, Purdue University, Indiana, 2011 1

3. About Cyanthiwigin F Isolated from the sea sponge Myrmekioderma styx, Cyanthiwigin F is one of 30 known cyanthiwigin natural products, which belongs to a larger class of bioactive molecules known as cyathins. Cyathins display a wide range of biological properties including antimicrobial activity, antineoplastic actions, stimulation of nerve growth factor synthesis, and κ-opioid receptor agonism. Cyanthiwigin F exhibits cytotoxicity activity against human primary tumour cells with a half-maximal inhibitory concentration of 3.1μg/ml. Synthetic Challenges posed by Cyanthiwigin F Construction of two all-carbon quaternary stereocentres at the A-B and B-C ring juncture. Fused 5-6-7 ring system. 2

4. Retrosynthesis 3

5. Synthesis of diketone through stereoablative and enantioselective double allylation 4

6. Stereochemical analysis of bis(β-ketoester) 5

7. Synthesis of bicyclic aldehyde through olefin metathesis 6

8. Final Stages and completion of total synthesis of cyanthiwigin F 7

9. Conclusion They achieved the catalytic enantioselective synthesis of the cyanthin diterpenoid (-)-cyanthiwigin F in 10 steps. Total yield is 1.8% Introduction of two chiral centers in one pot with excellent ee Tandem ring-closing and cross metathesis No protection and Deprotection involved. 8

10. Thank You 9