Volume 27, Issue 39 e202400608
Research Article

FeCl3 Catalyzed Synthesis of cis-Fused Reduced THC Analogues

Lucía Gurgone

Lucía Gurgone

Instituto de Química Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario-CONICET, Suipacha 531, S2002LRK Rosario, Argentina

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Tonino G. Adessi

Tonino G. Adessi

Instituto de Química Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario-CONICET, Suipacha 531, S2002LRK Rosario, Argentina

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Agustina La-Venia

Agustina La-Venia

Instituto de Química Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario-CONICET, Suipacha 531, S2002LRK Rosario, Argentina

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Vincent Gandon

Corresponding Author

Vincent Gandon

Institut de Chimie Moléculaire et des Matériaux d'Orsay (UMR CNRS 8182), Paris-Saclay University, bâtiment Henri Moissan, 17 avenue des sciences, 91400 Orsay, France

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Martín J. Riveira

Corresponding Author

Martín J. Riveira

Instituto de Química Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario-CONICET, Suipacha 531, S2002LRK Rosario, Argentina

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First published: 25 July 2024

Graphical Abstract

FeCl3 catalyzes the isomerization of 2-prenylated-2H-pyrans towards cis-fused tetrahydro-6H-benzo[c]chromene systems (cis-THC analogues). The same catalyst promotes the formation of these products via cyclocondensation of 1,3-dicarbonyl substrates and citral/farnesal-type aldehydes. The synthetic strategy could be applied to the racemic preparation of biologically relevant natural products cis-perrottetinene and Δ9-cis-tetrahydrocannabiorcol.

Abstract

Studies on a cycloisomerization reaction of 2-prenylated-2H-pyrans towards cis-fused tetrahydro-6H-benzo[c]chromene systems (reduced cis-THC analogues) are reported. The transformation is catalyzed by iron chloride and proceeds with the formation of two new bonds and two stereocenters diastereoselectively. The same catalyst also promotes the formation of these products via a one-pot tandem Knoevenagel condensation of 1,3-cyclohexanediones and citral or farnesal aldehydes, followed by cycloisomerization establishing a direct assembly of this important scaffold.

Conflict of Interests

The authors declare no competing financial interest.

Data Availability Statement

The data underlying this study are available in the published article and its online supplementary material.