Anomeric Samarium(III) Intermediates of N-Acetylneuraminic Acid from Anomeric 2-Pyridylsulfides
摘要:
Treatment of the anomeric 2-thiopyridyl derivative of N-acetylneuraminic acid (sialic acid or Neu5Ac) with samarium diiodide in the presence of aldehydes or ketones provides the corresponding C-sialylated derivatives in excellent yields. The efficiency of the reductive samariation of the anomeric 2-pyridyl sulfide moiety in the Neu5Ac series does not require any cosolvent or additive. This samarium Reformatsky-like reaction from anomeric 2-pyridyl sulfide derivatives of Neu5Ac provides an efficient and highly stereoselective access to alpha-2,6-C-disaccharides.