Synthesis of pinguisane-type sesquiterpenoids acutifolone A, pinguisenol, and bisacutifolones by a Diels-Alder dimerization reaction

Shiina, Junichi*; Oikawa, Masataka; Nakamura, Kensuke; Obata, Rika*; Nishiyama, Shigeru*

It is important to synthesize bio-active compounds which will affect DNA repair system. The total synthesis of pinguisane-type sesquiterpenoids, acutifolone A and pinguisenol, has been achieved by using the Mukaiyama aldol reaction as the key step. The intermolecular Diels-Alder reaction of these monomeric natural products successfully led to stereoselective dimerization, leading to bisacutifolones A and B. Theoretical calculations revealed that the dimerization reaction proceeded through the most stable transition state.