Regioselective Intramolecular Dipolar Cycloaddition of Azides and Unsymmetrical Alkynes

Enantioenriched allenylsilanes are used In three-component propargylation reactions with aldehydes and silyl ethers to form syn-homopropargylic ethers that contain an imbedded azide. These materials then undergo thermally Induced Intramolecular 1,3-dipolar cycloaddition reactions, resulting In unique fused ring systems containing 1,2,3-triazoles. The ability to modify all three components of the reaction allows for expedient access to compounds containing significant structural and stereochemical variation.