1. Stereospecific Intramolecular Carbenoid Insertions on Furanose Platforms as a Route to Branched-chain Sugars, C-Glycosides, and Fused Heterocycles
Peter Norris, Department of Chemistry, Youngstown State University, Youngstown, OH
Carbenoid Insertions: The rhodium(II)-catalyzed decomposition of various furanose-derived diazo-esters results in the intramolecular C-H insertion products as well as symmetrical dimeric ethers through apparent intermolecular insertion into water. Intramolecular insertion products formed represent examples of branched-chain sugars and also the heterocyclic portions of several classes of natural products.
One-pot Azidation: This reaction involves the displacement of azide from p-ABSA by an alcohol (or alkoxide), the generation of an intermediate sulfonate ester, and subsequent SN2 reaction with azide anion to afford the corresponding azide. The method has been expanded to employ microwave heating, which shortens reaction times quite significantly. It has become apparent why the use of DBU leads to lower yields; DBU appears to react with p-ABSA when the two are heated in solution. The resulting generation of free azide anion offers an alternative to using sodium azide in SN2 reactions on alkyl halides.