科研之友
微信
新浪微博
Facebook
分享链接
摘要
The first examples of the catalytic asymmetric 1,3-dipolar cycloaddition of azomethine ylides with acyclic activated 1,3-dienes (and 1,3-enynes) are described. Under copper catalysis, a selective cycloaddition at the terminal ,-CC bond is observed. In addition, depending on the ligand used, either the exo or the endo adduct can be obtained with high selectivity. Under appropriate reaction conditions, the acyclic 1,6-addition product is detected, suggesting a stepwise mechanism. The resulting C4-alkenyl-substituted pyrrolidines are suitable substrates for further access to polycyclic systems, as highlighted by the preparation of hexahydrochromeno[4,3-b]pyrrole and the tetracyclic core of the alkaloid gracilamine.
- 出版日期2015-3-16
