First Total Synthesis and Investigation of the X-ray Crystal Structure of the Pyrano[3,2-a]carbazole Alkaloid Clausenalansine A

Dedicated to Professor Tomáš Hudlický on the occasion of his 71^st birthday

Abstract

We describe the first total synthesis of the recently discovered pyrano[3,2-a]carbazole alkaloid clausenalansine A. The synthetic strategy for the construction of this formylpyrano[3,2-a]carbazole is based on a sequence of Buchwald–Hartwig coupling, palladium(II)-catalyzed oxidative cyclization, Lewis acid promoted annulation of the pyran ring, and chemoselective oxidation of a methyl to a formyl group.

Key words

carbazoles - alkaloids - annulation - catalysis - cyclization - natural products - total synthesis - palladium

Publication History

Received: 07 September 2020

Accepted after revision: 06 October 2020

Article published online:
05 November 2020

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