Rhodium-Catalyzed Cycloadditions between 3‑Diazoindolin-2-imines and 1,3-Dienes

Azepino­[2,3-b]­indoles
were regioselectively prepared
through rhodium-catalyzed formal aza-[4 + 3] cycloaddition between
3-diazoindolin-2-imines and 1,3-dienes in moderate to good yields.
Using 2-[(trimethylsilyl)­oxy]-1,3-butadiene as the diene component,
azepino­[2,3-b]­indol-4­(1H)-ones were
constructed. Furthermore, the reactions of cyclic dienes, such as
1,3-cyclohexadiene and 1,3-cyclopentadiene, furnished the corresponding
[3 + 2] cycloaddition products.

氮杂并[2,3-b]吲哚类化合物可通过铑催化的3-重氮吲哚-2-亚胺与1,3-二烯烃之间的形式氮杂[4+3]环加成反应实现区域选择性制备，产率中等至良好。以2-[(三甲基硅基)氧基]-1,3-丁二烯作为二烯组分时，可合成得到氮杂并[2,3-b]吲哚-4(1H)-酮。此外，以环状二烯烃（如1,3-环己二烯与1,3-环戊二烯）为底物的反应，可得到相应的[3+2]环加成产物。