6299-99-6Relevant articles and documents
Diversified Transformations of Tetrahydroindolizines to Construct Chiral 3-Arylindolizines and Dicarbofunctionalized 1,5-Diketones
Feng, Xiaoming,He, Qianwen,Liu, Xiaohua,Pan, Chenjing,Su, Zhishan,Wu, Zhikun,Zhang, Dong,Zhou, Yuqiao
supporting information, p. 15975 - 15985 (2020/10/18)
Enantioselective diverse synthesis of a small-molecule collection with structural and functional similarities or differences in an efficient manner is an appealing but formidable challenge. Asymmetric preparation and branching transformations of tetrahydroindolizines in succession present a useful approach to the construction of N-heterocycle-containing scaffolds with functional group, and stereochemical diversity. Herein, we report a breakthrough toward this end via an initial diastereo- A nd enantioselective [3 + 2] cycloaddition between pyridinium ylides and enones, following diversified sequential transformations. Chiral N,N′-dioxide-earth metal complexes enable the generation of optically active tetrahydroindolizines in situ, across the strong background reaction for racemate-formation. In connection with deliberate sequential transformations, involving convenient rearomatic oxidation, and light-active aza-Norrish II rearrangement, the tetrahydroindolizine intermediates were converted into the final library including 3-arylindolizine derivatives and dicarbofunctionalized 1,5-dicarbonyl compounds. More importantly, the stereochemistry of four-stereogenic centered tetrahydroindolizine intermediates could be efficiently transferred into axial chirality in 3-arylindolizines and vicinal pyridyl and aryl substituted 1,5-diketones. In addition, densely functionalized cyclopropanes and bridged cyclic compounds were also discovered depending on the nature of the pyridinium ylides. Mechanism studies were involved to explain the stereochemistry during the reaction processes.
Facile one-pot tandem synthesis of perfluoroalkylated indolizines under metal-free mild conditions
He, Dong,Xu, Yuhong,Han, Jing,Deng, Hongmei,Shao, Min,Chen, Jie,Zhang, Hui,Cao, Weiguo
, p. 938 - 944 (2017/01/25)
A direct metal-free method for the synthesis of perfluoroalkylated indolizines by means of DIPEA-promoted tandem C[sbnd]N/C[sbnd]C bond formation was developed. Various substituted pyridines and bromoacetyl derivatives with methyl perfluoroalk-2-ynoates proceeded smoothly in this mild transformation, and the desired products were obtained in good to excellent yields under air.
