A Concise, Stereocontrolled Total Synthesis of Rippertenol

1. A Concise, Stereocontrolled Total Synthesis of Rippertenol Scott A. Snyder Department of Chemistry, Columbia University J. Am. Chem. Soc. 2011, 133, 8850–8853

2. 1)Compact polycyclic framework 2)seven stereogeniccenters (two of which are quaternary) 3)Stereochemically rich but devoid of functionality to guide the formation of such complexity this molecule has not succumbed to laboratory synthesis in the more than 30 years since its original isolation

3. Retrosynthetic analysis

6. Takai/Ohshima-Lombardo olefination

9. Additional Approaches To Form Rippertenol’s 7-Membered Ring

10. the first total synthesis of rippertenol (1) has been achieved,selected privious effort(one methyl group could not be incorporated onto the final scaffold): Enantioselective Synthesis of 4-Desmethyl-3a-hydroxy-15-Rippertene. Peter Metz, Angew. Chem. Int. Ed. 2009, 48, 1157 –1159

14. Transition-Metal Peroxide Reactions. Synthesis of a-Hydroxycarbonyl Compounds from Enolates: J. Org. Chem. 1978, 43,188 – 196.

16. Thanks