ISSN:
0018-019X
Schlagwort(e):
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
3-Hydroxy-4-nitro-cyclohexanones from Ketones and 4-Nitrobutanoyl Chloride. A Ring Enlarging Five-Ring AnnulationThe 6-nitro-1, 3-diketones 5, 8, 9, 10, and 11, prepared by a 1:1 acylation at the C-atom of non-hindered lithium enolates with 4-nitrobutanoyl chloride according to equation 3, are cyclized with sodium hydrogen carbonate in aqueous tetrahydrofuran to give the hydroxy-nitro-ketones 13-17. Such cyclic nitroaldols are not formed from the cyclopentanone, -heptanone, and -octanone, nor from the aryl derivatives 4, 6, 7 and 12, respectively. Except for the vicinally trisubstituted compound 14, the cyclization products are isolated in diastereomerically pure form. A crystal structure X-ray analysis reveals the trans-decalone and the cisβ-nitroalcohol configurations of the product 13 from cyclohexanone (see Fig. 1-3). Acetalization to 21-25 and catalytic hydrogenation of the nitro groups furnishes the amino alcohols 27-31 (Table 4) which are substrates for the Tiffeneau-Demjanow rearrangement (see Schemes 2, 3, 4 and 5), From the stereoelectronic control of this sextett rearrangement we deduce the configurations of the 1, 4-diketones 35, 36, 39, 40, 43, 44, 46, and 47 formed under kinetic or thermodynamic conditions. The six-ring annulation with nitrobutanoic acid and the subsequent rearrangement are shown in Scheme 6; the sequence of reactions described here allows to carry out a ring enlargement of a cyclic ketone by one C-atom, with simultaneous annulation of a cyclopentanone ring.
Zusätzliches Material:
2 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/hlca.19810640314
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