Intramolecular Diels-Alder cycloadditions of fulvenes: Synthesis of the Kigelinol, Neoamphilectane and Kempanes skeletons

ORGN 195

Bor-cherng Hong,, Shang-Hung Chen1, Fon-Len Chen1, Ju-Hsiou Liao1, and Gene-Hsiang Lee2. (1) Department of Chemistry and Biochemistry, National Chung Cheng University, Chia-Yi, 621, Taiwan, (2) National Taiwan University, Instrumentation Center, College of Science, Taipei, 10601, Taiwan
A variety of polycyclic ring skeletons (e.g. kigelinol, neoamphilectane and kempenes systems) were prepared rapidly via Intramolecular Diels-Alder cycloadditions (IMDA) of fulvenes. The length of the tethers and the diversity of the substituents on the fulvene core dictate the nature of the IMDA pathway to afford various polycyclic ring systems. In addition, the tetracyclic core of kempene was prepared as enantiomeric pure product in 9 steps from commercially available methyl (R)-(+)-3-methylglutarate in 12% overall yield. The detail procedure and the relevant work will be discussed.