- XI. 90) (S)-Perilla alcohol (5) was transformed into (S)-7-(phenylthio)-p-menth-l-en-8-amine (11) in five steps. Condensation of this building block with 1 -(4-methoxyphenyIsulfonyl)-l H-indole-3-acetaldehyde (12) led to the expected imine 15 which cyclized in 54% yield to protected 20-(pheny1thio)hobartine 16 upon exposure to anh. HCOOH. Treatment of this intermediate with an alkylating reagent led to (+)-aristofruticosine protected in the indole moiety via an intramolecular, allylic nucleophilic displacement reaction. Subsequent reductive removal of the protecting group completed the first synthesis of the Aristotelia alkaloid (+)-aristofruticosine ((+)-4). This straightforward synthesis confirmed the tentative structure (+)-4, proposed by Bick and Hai, and established the hitherto unknown absolute configuration of this metabolite.
Taken in part from the diploma thesis of R. B., ETH Zurich, 1988. Racemic and optically pure samples of sorelline (2) have been synthesized recently in our laboratory [6] . Hobartin-20-01 (3) has been isolated from Aristotelia australasica [8] and may well represent the biological precursor of 2 and 4.
The authors would like to express their