A rearrangement–cycloaddition approach to spiro-fused indanones

Goldring, William; Bouazzaoui, Samira; Malone, John F.

doi:10.1016/j.tetlet.2010.12.086

Cited by 3 publications

(3 citation statements)

References 30 publications

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“…As outlined in Scheme , the ketone intermediates that are needed for the Friedländer annulation en route to 1 and 2 are readily available in two steps from suitable bicyclic starting materials, while a more complex sequence had to be devised for the preparation of 3 . The synthesis of 1 starts with a rearrangement of 4‐chromanone with AlCl 3 to afford indanone 4 , in 60 % yield. For the subsequent annulation step, it is imperative to protect the phenolic OH which can be done in good yield by treatment with KOH and MeI.…”

Section: Resultsmentioning

confidence: 99%

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Hydrogen Bonded Phenol‐Quinolines with Highly Controlled Proton‐Transfer Coordinate

et al. 2016

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A series of polycyclic phenols with intramolecular hydrogen bonds (IMHB) to quinolines was synthesized by Friedländer annulation of cycloalkanone‐functionalized anisoles with 2‐aminobenzaldehyde. The prepared compounds represent the first series of IMHB phenols in which the substitution and conjugation patterns between the phenols and the hydrogen bond acceptors are kept constant, and in which comparable electronic interaction between the two subunits is thus ensured. The distance and relative orientation between the phenolic OH and the quinolone nitrogen atom is controlled by 1,3‐cycloalkadienes of different ring sizes to which the phenol and quinoline subunits are formally annulated. 1H δ(OH) chemical shift and X‐ray crystal structure characterization support the conclusion that the size and conformational preference of the 1,3‐cycloalkadiene rings control the H‐bond geometry and strength. As a result, the oxygen to nitrogen distances differ by as much as 0.30 Å across the series.

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Section: Resultsmentioning

confidence: 99%

“…7‐Hydroxyindanone (4): , , A round bottle flask loaded with 5.0 g (37.8 mmol) of 4‐chromanone and 10.0 g (97.5 mmol) of anhydrous powder AlCl 3 was heated at 180 °C for 20 min and then at 200 °C for 30 min. The reaction mixture was cooled down to room temperature and HCl 37 % was added.…”

Section: Methodsmentioning

confidence: 99%

Hydrogen Bonded Phenol‐Quinolines with Highly Controlled Proton‐Transfer Coordinate

et al. 2016

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“…The direct electrophilic ring opening of 4‐chromanone with a nucleophile would be an ideal route to synthesize various β ‐substituted o ‐hydroxyphenyl ethyl ketones. However, it suffered from intramolecular cyclization (Scheme 1f) [19a,b] . Herein, we report our results on an effective two‐step protocol that allows synthesis of β ‐substituted o ‐hydroxyphenyl ethyl ketones starting from 4‐chromanone and consisting in i) the base promoted ring opening of 4‐chromanone to give β ‐ethoxyl o ‐hydroxyphenyl ethyl ketone 1 a and ii) a BF 3 ⋅Et 2 O mediated substitution through the in situ generation of boron difluoride complex 1 b [20] followed by releasing one molecular ethanol to form boron difluoride complex 1 c [21] that undergoes intermolecular Michael addition to provide the desired β ‐substituted o ‐hydroxyphenyl ethyl ketones (Scheme 1g).…”

Section: Introductionmentioning

confidence: 99%

Two‐Step Access toβ‐Substitutedo‐Hydroxyphenyl Ethyl Ketones from 4‐Chromanone and its Application in Preparation of a Silica‐Supported Cobalt(II) Salen Complex

et al. 2021

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The o‐hydroxyphenyl ethyl ketone skeleton is prevalent in many biologically active natural products and active pharmaceutical ingredients. Herein, a two‐step protocol has been developed for synthesis of various β‐substituted o‐hydroxyphenyl ethyl ketones. A base‐mediated ring opening of 4‐chromanone was used to introduce the β‐ethoxyl o‐hydroxyphenyl ethyl ketone intermediary, followed by nucleophile substitution under BF3 ⋅ Et2O assisted conditions to give the desired β‐carbon, nitrogen, or thiol substituted o‐hydroxyphenyl ethyl ketones. With the aid of this protocol, a silica‐supported cobalt(II) salen complex was successfully prepared and its structure was confirmed by FTIR, 13C MAS NMR, UV‐Vis absorption, and XPS spectra. The immobilized cobalt(II) salen catalyst not only displayed comparable catalytic activity in the synthesis of several heterocycles including 1,3‐oxazolidine, benzimidazole, and benzoxazole as compared with their homogeneous counterparts, but also could be recycled for several times without obvious loss of its catalytic activity.

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Aminocatalytic Asymmetric exo-Diels–Alder Reaction with Methiodide Salts of Mannich Bases and 2,4-Dienals to Construct Chiral Spirocycles

Zhang

Zhou

et al. 2013

Org. Lett.

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A rearrangement–cycloaddition approach to spiro-fused indanones

Cited by 3 publications

References 30 publications

Hydrogen Bonded Phenol‐Quinolines with Highly Controlled Proton‐Transfer Coordinate

Hydrogen Bonded Phenol‐Quinolines with Highly Controlled Proton‐Transfer Coordinate

Two‐Step Access toβ‐Substitutedo‐Hydroxyphenyl Ethyl Ketones from 4‐Chromanone and its Application in Preparation of a Silica‐Supported Cobalt(II) Salen Complex

Aminocatalytic Asymmetric exo-Diels–Alder Reaction with Methiodide Salts of Mannich Bases and 2,4-Dienals to Construct Chiral Spirocycles

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