Efficient and novel one-pot synthesis of polycycles bearing cyclols by FeCl3-promoted [2 + 2] cycloaddition: application to cannabicyclol, cannabicyclovarin, and ranhuadujuanine A

Li, Xin; Lee, Yong Rok

doi:10.1039/c3ob42110d

Cited by 28 publications

(12 citation statements)

References 57 publications

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“…Cannabicitran (citrylidene-cannabis, bicyclo-CBC, 6 ) and Δ 8 - iso - cis -THC (cyclo-CBC, 7 ) are derived from the protonation of the chromene olefin bond and formation of a benzyl cation, next trapped by the terminal isoprenyl double bond, with termination either by proton loss to Δ 8 - iso - cis -THC ( 7 ) or by intramolecular oxygen trapping to cannabicitran ( 6 ). The structure of the third compound, cannabicyclol (CBL, 8 ), was confirmed by comparison with an authentic sample prepared by intramolecular [2 + 2] photocycloaddition of CBC (45% yield) and CBC treatment with FeCl 3 (65% yield) . The three compounds formed in the pyrolytic study had already been described from the treatment of CBC and other cannabinoids with acids and/or by heating or irradiation .…”

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confidence: 73%

One-Pot Total Synthesis of Cannabinol via Iodine-Mediated Deconstructive Annulation

et al. 2019

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The thermal degradation of cannabichromene (CBC, 3) is dominated by cationic reactions and not by the pericyclic rearrangements observed in model compounds. The rationalization of these differences inspired the development of a process that coupled, in an aromatization-driven single operational step, the condensation of citral and alkylresorciniols to homoprenylchromenes and their in situ deconstructive annulation to benzo[c]chromenes. This process was applied to a total synthesis of cannabinol (CBN, 5) and to its molecular editing.

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confidence: 73%

One-Pot Total Synthesis of Cannabinol via Iodine-Mediated Deconstructive Annulation

et al. 2019

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“…The 6–6–5–4 meroterpenoid ring system (Figure b) is far more common in plant natural products, including the well-known cannabicyclol class of phytocannabinoids, and it can be synthesized via biomimetic, intramolecular [2 + 2] cycloadditions under photochemical, thermal, or acidic conditions and the merosesquiterpenoids fastinoid B ( 8 ) and rhodonoid B ( 9 ) .…”

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confidence: 99%

Biomimetic Total Synthesis of the Rubiginosin Meroterpenoids

et al. 2020

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Total synthesis of the Rhododendron meroterpenoids rubiginosins A and G, which both contain unusual 6−6−6−4 ring systems, has been achieved using a bioinspired cascade approach. Stepwise synthesis of these natural products, and the related 6−6−5−4 meroterpenoids fastinoid B and rhodonoid B, from naturally occurring chromene precursors is also reported.Rhododendron plants are a rich source of stereochemically complex, polycyclic meroterpenoids. Among the various possible scaffolds, the 6−6−6−4 ring system (Figure 1a) is

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“…In addition to their unique motifs, these novel meroterpenoids possess anti-HSV-1 activity ( 1 ) and inhibitory effects on PTP1B ( 8 ). Although synthesized as early as 1984, ranhuadujuanine B was not isolated until 2011 from Rhododendron anthopogonoides. , This unique structural motif has attracted an array of synthetic efforts. , …”

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confidence: 99%