Allyl Cyanate/Isocyanate Rearrangement in Glycals: Stereoselective Synthesis of 1-Amino and Diamino Sugar Derivatives.

The [3,3]-sigmatropic allyl cyanate/isocyanate rearrangement of glycals in the presence of -, -, and -nucleophiles afforded β--glucosyl and galactosyl carbamates, ureas, and amides in good yields. The unsaturated products were elaborated to -glycosides by dihydroxylation, to 1,3-diaminosugars by tethered aminohydroxylation, or to 1,2-diaminosugars by iteration of the sigmatropic rearrangement. This metal-free methodology represents an excellent and general method for the stereoselective synthesis of -glycosides and diamino sugars with complete transmission of stereochemical information.