Multicomponent Synthesis of 6H-Dibenzo[b,d]pyran-6-ones and a Total Synthesis of Cannabinol

A multicomponent domino reaction that affords 6H-dibenzo[b,d]pyran-6-ones is reported. The overall transformation consists of six reactions: Knoevenagel condensation, transesterification, enamine formation, an inverse electron demand Diels–Alder (IEDDA) reaction, 1,2-elimination, and transfer hydrog...

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Bibliographic Details
Published in:Organic letters 2012-01, Vol.14 (1), p.310-313
Main Authors: Nandaluru, Penchal Reddy, Bodwell, Graham J
Format: Article
Language:English
Subjects:
Cannabinol - chemical synthesis
Hydrogenation
Lactones - chemical synthesis
Molecular Structure
Phenanthrenes - chemical synthesis
Pyrans
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Summary:A multicomponent domino reaction that affords 6H-dibenzo[b,d]pyran-6-ones is reported. The overall transformation consists of six reactions: Knoevenagel condensation, transesterification, enamine formation, an inverse electron demand Diels–Alder (IEDDA) reaction, 1,2-elimination, and transfer hydrogenation. Both the diene and dienophile for the key inverse electron demand Diels–Alder (IEDDA) step are generated in situ by secondary amine-mediated processes. In most cases, the yields (10–79%) are considerably better than those obtained using a stepwise process. This methodology is employed in a concise total synthesis of cannabinol.
ISSN:1523-7060
1523-7052
DOI:10.1021/ol2030636