The [4+1] cycloaddition reaction of bifunctional amino reagents has been achieved with in situ formed aza‐ortho‐quinonemethides. Specifically, N‐(tosyloxy)carbamates were used as an N1 synthon and bifunctional amino reagents for this transformation, which provides a metal‐free, catalyst‐free, and oxidant‐free strategy to form nitrogen‐nitrogen bonds.
Synthesis of Furo[3,2-<i>b</i>]quinolines and Furo[2,3-<i>b</i>:4,5-<i>b′</i>]diquinolines through [4 + 2] Cycloaddition of Aza-<i>o</i>-Quinone Methides and Furans
作者:Lu Lei、Yi-Yun Yao、Li-Juan Jiang、Xiuqiang Lu、Cui Liang、Dong-Liang Mo
DOI:10.1021/acs.joc.9b02953
日期:2020.3.6
An approach for the construction of furo[3,2-b]quinolines and furo[2,3-b:4,5-b']diquinolines is developed through a metal-free [4 + 2] cycloaddition of easily available in situ generated aza-o-quinone methides and furans. The reaction tolerates a wide range of aza-o-quinone methides and substituted furans to afford the corresponding dihydro- or tetrahydrofuroquinolines in good to excellent yields.
The base-induced formal [4+3] cycloaddition reaction of C,N-cyclic azomethine imines with aza-ortho-quinone methides, generated in situ, is reported. This protocol provided an efficient method for the synthesis of biologically important 1,2,4-triazepine derivatives, with a wide substrate scope and excellent functional-group tolerance, and it gives moderate to excellent yields under mild conditions
A method for the preparation of indolines via palladium-catalyzed aerobic intramolecular allylic CH activation was developed. Oxygen was successfully used as oxidant with catalytic amount of 1,4-benzoquinone. 16 examples were reported, the majority of substrates gave moderate to good yields.
(4 + 2) cyclization of aza-<i>o</i>-quinone methides with azlactones: construction of biologically important dihydroquinolinone frameworks
作者:Hai-Qing Wang、Wenjing Ma、Ao Sun、Xin-Yue Sun、Chao Jiang、Yu-Chen Zhang、Feng Shi
DOI:10.1039/d0ob02388d
日期:——
A base-promoted (4 + 2) cyclization of N-(o-chloromethyl)aryl amides with azlactones was established, which helped construct biologically important dihydroquinolinone frameworks in good yields.