ISSN:
0018-019X
Schlagwort(e):
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Synthesis of Ketoses by Chain Elongation of 1-Deoxy-1-nitroaldoses. Nucleophilic Additions and Solvolysis of Nitro EthersA method for the preparation of chain elongated uloses based upon the base-catalyzed addition of 1-deoxy-1-nitroaldoses to aldehydes and Michael acceptors and subsequent solvolytic replacement of the nitro group by a hydroxy group is described. Thus, addition of 1, 3 and 9 to formaldehyde, followed by solvolysis gave the chain elongated ulose derivatives 2, 8 and 10 (63-76%), respectively. The configuration at the anomeric center of the addition products was deduced from 13C-NMR. spectra and mutarotation. In the case of 3, the primary addition products 4 and 6 were isolated and acetylated to 5 and 7. The nitro derivatives 4-7 do not follow Hudson's rule of isorotation. Addition of 1 to benzaldehyde (44%) and to nonanal (74%) preceded with a small degree of diastereoselectivity to give 15a/15b, and 11/12, respectively. The configuration of the secondary hydroxyl group of 12 was determined by correlation with methyl 2-hydroxydecanoate (14). Addition of 1 to the galacroaldehyde 16 gave a single compound 17 (78%). The structure of this dodecosulose was determined by X-ray crystallography. Solvolysis of the acetylation product 18 in formamide gave the hemiacetal 19 (69%). Michael addition of 1 to acrylonitrile, methyl vinyl ketone and cyclohexenone under solvolytic conditions gave the hemiacetals 27, 30 and 31a,b (49%, 71% and 76%, respectively). Under non-solvolytic conditions (Bu4NF), 1 reacted with acrylonitrile, and crotononitrile to give the anomeric nitro ethers 23 and 24 (67%) and 25 and 26 (84%). respectively. Similarly. 3 added to acrylonitrile to give 28 and 29 (55%, 4:1). This reaction appears to proceed under kinetic control. Addition of 1 to ethyl propiolate and solvolysis yielded the unsaturated spirolactone 32 (50%) and the hemiacetal 33 (17%). Hydrogenation of 32 gave the saturated spirolactone 34 (100%) which was also obtained from 1 and methyl acrylate (63%). Addition of 1 to dimethylmaleate gave the unsaturated ester 35 (48%).
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/hlca.19820650730
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