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Short Paper | Special issue | Vol 84, No. 2, 2012, pp.1325-1334
Published online, 8th August, 2011
DOI: 10.3987/COM-11-S(P)67
Synthetic Studies on Paspaline: Lewis Acid-Mediated Sequential Construction of A-E Ring Skeleton

Kentaro Okano, Yu Yoshii, and Hidetoshi Tokuyama*

*Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan


The common pentacyclic skeleton of indole diterpene alkaloids, paspaline and its derivatives was constructed by a sequential reaction. The appropriate choice of the protecting group on the indole nitrogen was critical for the formation of bis(methylthio)allylic alcohol, which then underwent sulfonium ion formation and intramolecular electrophilic C-C-bond formation at the indole 3-position.