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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 2443-2461 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new ring expansion method using the cyclofragmentation of epoxysulfones; a synthesis of rac. muscone.Starting from the readily available cyclododecanone 1 the hydroxy sulfone 5 has been prepared using standard procedures. Subsequent dehydration followed by an acidic equilibration resulted in a mixture of two endocyclic olefines, from which the olefin 7 showing the (E)-configuration could be isolated by fractional crystallization. Oxidation of 7 produced the epoxy sulfones 8 and 9. The epoxy sulfone 8 was cyclized to the hydroxy sulfone 10 without any detectable amount of the corresponding epimer 11. Fragmentation of the intermediate 10 using KOTB produced pure (E)-4-muscenone 12. The epoxy sulfone 9 was cyclized to a mixture of the two epimeric hydroxy sulfones 14 and 15. Fragmentation of the two crystalline hydroxy sulfones 14 or 15 with KOTB produced a mixture of 12 and 16. The ‘one-pot’ preparation of (E)-4-muscenone 12 starting from 8 could also be accomplished. The configurational assignements within this serie are based upon the data of an X-ray analysis of the hydroxy sulfone 10.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A chiral economic synthesis of (R)- and (S)-muscone using the cyclofragmentation of epoxysulfonesStarting with isobutyric acid (2) and using a microbiological oxidation with pseudomonas putida (S)-β-hydroxy-iso-butyric acid (3) has been prepared. From this /pseudosymmetrical: (see text) intermediate the two enantiomeric bromo derivatives 8 (R) and 20 (S) have been synthesized (cf. scheme 4) by altering the sequence of the reactions (cf. scheme 3). A Grignard reaction starting from the two bromo compounds 8 and 20 and from cyclododecanone 1 produced after hydrogenolysis the two enantiomeric dialcohols 9 and 21 (1 + 8 → 9, 1 + 20 → 21, cf. scheme 5). The subsequent transformations led to the two enantiomeric olefin derivatives 12 and 24. Oxidation of 12 with peracid produced a mixture of the two epoxy-sulfones 13 and 14 (cf. scheme 6). The olefin-derivative 24 was oxidized to the corresponding mixture of 25 and 26. A one pot cyclofragmentation (cf. [4] and scheme 6) produced a mixture of (E)- and (Z)-3-methylcyclopentadec-4-en-1-one (13 + 14 → 15 + 16, 25 + 26 → 27 + 28). The final hydrogenation led to natural (R)- and unnatural (S-muscone (3-methylcyclopentadecanone). The achiral starting material has been transformed to the desired optically active target products without loss of material with undesired absolute configuration. The authors used the notion of chiral economic synthesis to characterize synthetic sequences with the above mentioned features.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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