A highly efficient synthetic route to pterocarpenes and coumestans is described. BCl3-mediated dehydrative cyclization of 1,3-diaryloxyacetones under mild conditions permitted regioselective ring closure to afford 3-((2-iodoaryloxy)methyl)benzofurans which were converted to the corresponding pterocarpenes by Pd-catalyzed intramolecular direct arylation. The subsequent benzylic oxidation led to coumestans. This sequence was applied to the formal syntheses of coumestrol and the proposed structure of plicadin as well as total syntheses of flemichapparins B and C.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (2014R1A2A1A11050491). This research was also supported in part by the Nano Material Technology Development Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry