Total synthesis of icetexane diterpenoids via a metal-mediated cycloisomerization

ORGN 718

Eric M. Simmons, eric_simmons@berkeley.edu, Department of Chemistry, University of California, Berkeley, CA 94720 and Richmond Sarpong, rsarpong@berkeley.edu, Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720.
A strategy for the synthesis of icetexane diterpenoid natural products, which possess anti-Chagastic activity, has been developed. In the key transformation, the tricyclic icetexane core is formed via the metal-mediated cycloisomerization of an alkynyl indene precursor (5). While a number of transition metal-complexes were ineffective for the desired transformation, the use of Ga(III) salts gave a quantitative conversion of the enyne to the tricyclic cycloheptadiene framework (6). This transformation represents the first example of an enyne cycloisomerization involving an indene to produce a cycloheptadiene. The utility of this strategy has been demonstrated in the first total synthesis of (±)-salviasperanol (1).

 

Total Synthesis, Materials, Molecular Recognition, Process R&D, and Physical Organic Chemistry
8:00 PM-10:00 PM, Wednesday, 13 September 2006 Moscone Center -- Hall D, Poster

Division of Organic Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006