Synthesis of enantiomerically pure hydroxylated pyrroline N-oxides from d-ribose
摘要:
A convenient way to obtain enantiomerically pure hydroxylated pyrroline N-oxides is reported. The key step is the formation of omega-oxo criciates from (D)-ribose and a subsequent 1,3-azaprotio cyclotransfer reaction of the resulting oximino alkenoate derivatives. The stereochemistry of the nitrones obtained is discussed in relation to that of the starting compounds. (c) 2006 Elsevier Ltd. All rights reserved.
The stereoselective synthesis of and unsaturated Wittig products derivated from 2,3--isopropylidene-5--trityl--ribofuranose (3) and 2,3:5,6-di--isopropylidene--mannofuranose (4) was described, as well as their stereo-specific cyclization induced by iodine, to C-glycosides. The absolute configurations at the anomeric center and at the C-α of the aglycone rest, were established by chemical and spectroscopic