enantioselective Pd(II)-catalyzed intramolecularoxidative amination reaction was developed utilizing the commercially available chiral X-type ligand (1S)-(+)-camphorsulfonic acid. The Wacker-type cyclization produced chiral indoline products with enantioselectivies up to 45% ee. Electronic structure calculations employing density functional theory support a trans-aminopalladation mechanism.
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
Accessing benzooxadiazepines<i>via</i>formal [4 + 3] cycloadditions of aza-<i>o</i>-quinone methides with nitrones
作者:Yong-Sheng Zheng、Liang Tu、Li-Mei Gao、Rong Huang、Tao Feng、Huan Sun、Wen-Xuan Wang、Zheng-Hui Li、Ji-Kai Liu
DOI:10.1039/c8ob00201k
日期:——
An unprecedented and efficient [4 + 3] cycloaddition of N-(ortho-chloromethyl)aryl amides with nitrones has been developed. This approach provides easy access to a series of seven-membered benzooxadiazepine derivatives in good to excellent yields (up to 99% yield) under mild reaction conditions.