Online article for Non-subscribers

Pay per view

Heterocycles has a pay-per-view service for Non-subscribers.
You will be able to directly purchase the full text article through PayPal.
Your purchased Paper can be downloaded after the payment is completed.
An e-mail will be sent the URL to download the paper.
If you have any questions, please contact: purchase@heterocycles.com

Price: ¥ 4,320 (Yen only)
Period: This Article can be accessed for 7 days.

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

Abstract

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.