Fused Triazoles via Tandem Reactions of Activated Cinchona Alkaloids with Azide Ion. Second Cinchona Rearrangement Exemplified

[reaction: see text] Intramolecular 1,3-dipolar cycloadditions of cinchona azides to the C10-C11 alkyne and C10-C11 olefin unit of the alkaloid have been designed via tandem strategy. A variety of fused triazoles and triazolines with a bis-azahomotwistane skeleton have been prepared. In trifluoroethanol, O-mesylcinchonidine 7-OMs and NaN(3) furnish triazole 8 as well as cage-expanded 1,5-diazatricyclo[4.4.1.0(3,8)]undecane derivative 10. Both fused triazoles 8 and 10 are formed with retention of configuration at C9 and C3, respectively. 1-Azabicyclo[3.2.2]cage expansion is shown to be reversible.