Synthesis of Azacyclic Nucleoside Analogues via Asymmetric [3 + 2] Cycloaddition of 9‑(2-Tosylvinyl)‑9<i>H</i>‑purines ZhangDan-Jie XieMing-Sheng QuGui-Rong GaoYao-Wei GuoHai-Ming 2016 With 9-(2-tosylvinyl)-9<i>H</i>-purines as the dipolarophiles, a series of chiral azacyclic nucleosides with four continuous stereocenters were obtained in 86–99% yields, >20:1 dr, and 94 → 99% ee via the Cu­(I)-catalyzed asymmetric [3 + 2] cycloaddition. Both (<i>E</i>)- and (<i>Z</i>)-9-(2-tosylvinyl)-9<i>H</i>-purines were suitable dipolarophiles, enriching the structure diversity of azacyclic nucleosides. Furthermore, when α-methyl imino ester was explored, the corresponding azacyclic nucleoside with a chiral quaternary stereocenter could also be afforded with excellent results.