A Useful Route to Optically Active 4-Oxygenated 4,5-Dihydroisoxazoles
摘要:
Optically active iodotosylates were prepared from carbohydrate precursors and were transformed by the action of excess sodium nitrite/propyl nitrite to bicyclic 4-oxygenated 4,5-dihydro-3-nitroisoxazoles.
Primary amines reacted upon 4,6-ditosylates of glucopyranosides to give an azetidine ring fused on C-4 and C-6 of the pyranose ring. On the other hand, the 4,6-ditosylate of benzyl mannopyranoside led to the 4,6-diamino-4,6-dideoxy derivative in a good yield. All the compounds and their precursors were identified by H-1 and C-13 NMR spectroscopy. Assignments of proton signals were made unambiguously using homodecoupling experiments. (C) 1997 Elsevier Science Ltd.
Glycosyl thiocyanates having hydroxyl groups protected with acetyl or benzoyl groups react readily at −40°C with Grignard reagents to afford the corresponding alkyl or aryl thioglycosides in good yields. Monosaccharide derivatives having the SCN grouping at other positions form under similar conditions thioethers. Axial thiocyanates do not react. Elevated temperatures induce side reactions leading
Primary amines reacted upon 4,6-ditosylates of glucopyranosides to give an azetidine ring fused on C-4 and C-6 of the pyranose ring. On the other hand, the 4,6-ditosylate of benzyl mannopyranoside led to the 4,6-diamino-4,6-dideoxy derivative in a good yield. All the compounds and their precursors were identified by H-1 and C-13 NMR spectroscopy. Assignments of proton signals were made unambiguously using homodecoupling experiments. (C) 1997 Elsevier Science Ltd.
A Useful Route to Optically Active 4-Oxygenated 4,5-Dihydroisoxazoles
作者:Peter A. Wade、Sharmila S. Shah、Lakshmi Govindarajan
DOI:10.1021/jo00103a007
日期:1994.12
Optically active iodotosylates were prepared from carbohydrate precursors and were transformed by the action of excess sodium nitrite/propyl nitrite to bicyclic 4-oxygenated 4,5-dihydro-3-nitroisoxazoles.