1. Convergent Synthesis of Naphthylisoquinoline Alkaloids: Total Synthesis of (+)-O-Methylancistrocline
- Author
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Mark A. Rizzacasa, Manuela Schäffer, Phung Chau, Gerhard Bringmann, Ivona R. Czuba, and Klaus-Peter Gulden
- Subjects
chemistry.chemical_compound ,Atropisomer ,chemistry ,Tetrahydroisoquinoline ,Stereochemistry ,Organic Chemistry ,Enantioselective synthesis ,Convergent synthesis ,Total synthesis ,Ether ,Oxazoline ,Derivative (chemistry) - Abstract
A highly convergent synthesis of the methyl ether derivative 2a of the naphthylisoquinoline alkaloid ancistrocline (2) is described. The key step involves a stereoselective biaryl coupling between the chiral oxazoline 3 and the Grignard reagent 4 derived from the optically active tetrahydroisoquinoline 8. The atropisomeric mixture was then converted to the separable acetamides 11 and 12, which were obtained in a ratio of 16:84 and an overall yield of 32% for the three steps. The major atropisomer 12 was then converted into O-methylancistrocline (2a), which was identical to a semisynthetic sample derived from the related alkaloid ancistrocladinine (14).
- Published
- 1996