A Novel Pentannulation Sequence. Facile Access to Key Intermediates for the Synthesis of <i>Exaltone</i>® and Muscone

Fehr, Charles

doi:10.1002/hlca.19830660817

Cited by 13 publications

References 17 publications

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ChemInform Abstract: A NOVEL PENTANNULATION SEQUENCE. FACILE ACCESS TO KEY INTERMEDIATES FOR THE SYNTHESIS OF EXALTONE AND MUSCONE

Fehr¹

1984

Chemischer Informationsdienst

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SummaryTreatment of the sulfonyl ketones 1 a and 1 b with potassium t-butoxide in toluene or with potassium hydroxide in toluene/dimethyl sulfoxide affords in high yield the bicyclic dienes 3 a and 3 b, important precursors for Exaltone@ and (+)-muscone. An application of this novel pentannulation sequence is demonstrated for the sulfonyl ketones 6, 10, and 14. An intermolecular variant is exemplified by the synthesis of diene 22.The preceding paper [2] described a new synthesis of (*)-muscone based on the intramolecular condensation of a sulfonyl lactone followed by reductive removal of the sulfonyl group. We now report the analogous intramolecular reaction of the sulfonyl ketones 1 a and 1 b, leading to the bicyclo[l0.3.0]pentadecenes 4 a and 4b, which are key intermediates for the synthesis of Exaltone@ and (+)-muscone [3] (Scheme 1 ) .The intramolecular cyclization of the readily available sulfonyl ketone 1 a [l] [2] using t-BuOK (1.5 equiv.) in toluene at 50" ' ) gave the fl, y-unsaturated sulfone 2 a in 88 YO yield (Scheme 1 ) 3). Sulfone 2 a may be directly reduced to 4 a (cJ: [5]) but for convenience we preferred to exploit the allylic nature of the sulfonyl group for its possible elimination4). Accordingly, when sulfonyl ketone 1 a was treated with an excess of t-BuOK in toluene at reflux, the allylic sulfone 2 a formed in situ was directly transformed to the diene 3 a (9: 1 isomeric mixture) in 83% yield. Alternatively, NaOMe or KOH in hot toluene containing a small amount of DMSO effected the same conversion; in the absence of DMSO, the reaction stopped at the bicyclic sulfone 2a.

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ChemInform Abstract: A NOVEL PENTANNULATION SEQUENCE. FACILE ACCESS TO KEY INTERMEDIATES FOR THE SYNTHESIS OF EXALTONE AND MUSCONE

Fehr¹

1984

Chemischer Informationsdienst

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A Novel Three‐Carbon Ring Expansion Sequence Synthesis of Exaltone® and (±)‐Muscone

Fehr

1983

Helvetica Chimica Acta

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Intramolecular Grignard‐type reaction of the bromo lactones 3 and 8 affords the macrocycles 10, 11, 12 and 13, 14, 15, respectively. More efficiently, 10 and 13 are obtained by intramolecular nucleophilic attack of the carbanions derived from the sulfonyl lactones 20 and 22 and in situ reduction of the intermediate sulfones 21 and 23. The macrocylic hydroxy ketones 10 and 13 are converted into Exaltone® (2) and muscone (1), respectively.

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A Short Synthesis of (±)‐Muscone

Rautenstrauch

Snowden

Linder

1990

Helvetica Chimica Acta

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A Novel Pentannulation Sequence. Facile Access to Key Intermediates for the Synthesis of Exaltone® and Muscone

Cited by 13 publications

References 17 publications

ChemInform Abstract: A NOVEL PENTANNULATION SEQUENCE. FACILE ACCESS TO KEY INTERMEDIATES FOR THE SYNTHESIS OF EXALTONE AND MUSCONE

ChemInform Abstract: A NOVEL PENTANNULATION SEQUENCE. FACILE ACCESS TO KEY INTERMEDIATES FOR THE SYNTHESIS OF EXALTONE AND MUSCONE

A Novel Three‐Carbon Ring Expansion Sequence Synthesis of Exaltone® and (±)‐Muscone

A Short Synthesis of (±)‐Muscone

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