Desoxy‐nitrozucker. 3. Mitteilung. Synthese von Ketosen durch Kettenverlängerung von 1‐Desoxy‐1‐nitro‐aldosen. Nucleophile Additionen und Solvolyse von Nitroaethern

Abstract

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%).