Stereoselective Synthesis of 1,2,3-Triazolooxazine and Fused 1,2,3-Triazolo Derivatives

Abstract

The stereoselective synthesis of 1,2,3-triazolooxazine and fused 1,2,3-triazolo--lactone by applying chemoenzymatic methods is described. trans-2-Azidocyclohexanol was successfully resolved by Novozyme 435 with an ee value of 99%. Installation of the alkyne moiety on the enantiomerically enriched azidoalcohol by O-alkylation, followed by intramolecular azidealkyne [3+2] cycloaddition resulted in the desired 1,2,3-triazolooxazine derivative. Enantiomerically pure azidocyclohexanol was also subjected to the Huisgen 1,3-dipolar cycloaddition reaction with dimethylacetylene dicarboxylate, followed by intramolecular cyclization of the corresponding cycloadduct, to furnish a fused 1,2,3-triazolo--lactone.