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Concise approach to the aromatic yohimboid and protoberberine alkaloids via intramolecular Diels-Alder reactions

✍ Scribed by Stephen F. Martin; Leo S. Geraci

Publisher
Elsevier Science
Year
1988
Tongue
French
Weight
249 KB
Volume
29
Category
Article
ISSN
0040-4039

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✦ Synopsis

The aromatic yohimboid indole alkaloid oxogambirtannine (9) was synthesized in high yield via the intramolecular [4 + 21 cycloaddition/dehydrogenation of the substituted B-carboline W, which was readily accessed by the reaction of 10 with the acid chloride 11 in the presence of the diene 12. In a similar manner the prototypical protoberberine skeleton 20 was rapidly constructed upon cyclization of the substituted isoquinoline 17. Intramolecular [4 + 21 cycloaddition reactions have aheady been successfully exploited in this laboratory2w3 as the key steps in the syntheses of several pharmacologically active monoterpenoid indole alkaloids.4 The general

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