- Diversified Transformations of Tetrahydroindolizines to Construct Chiral 3-Arylindolizines and Dicarbofunctionalized 1,5-Diketones
-
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.
- 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 dicarbofunctionalization of (: E)-alkenyloxindoles with pyridinium salts by chiral Lewis acid/photo relay catalysis
-
A highly efficient enantioselective dicarbofunctionalization reaction of (E)-alkenyloxindoles with pyridinium salts was realized. The process includes the chiral N,N′-dioxide-Sc(iii) complex-catalyzed regio-, diastereo-, and enantioselective [3+2] cycloaddition reaction and the following photo-promoted aza-Norrish II type rearrangement. A series of 2-pyridyl substituted oxindole derivatives were obtained in good yields with moderate to good diastereo- and enantioselectivities. This journal is
- Zhang, Dong,Dong, Shunxi,He, Qianwen,Luo, Yao,Liu, Yun,Liu, Xiaohua,Feng, Xiaoming
-
supporting information
p. 12757 - 12760
(2020/11/02)
-
- Visible-Light-Induced Carbo-2-pyridylation of Electron-Deficient Alkenes with Pyridinium Salts
-
A simple and practical visible-light-induced carbo-2-pyridylation of electron-deficient alkenes with readily available N-benzoylmethylpyridinium bromides is reported. More than 40 examples are presented and proceed in greater than 80 % yield (on average)
- Hu, Rong-Bin,Sun, Shuai,Su, Yijin
-
supporting information
p. 10877 - 10880
(2017/08/30)
-
- Nucleophilicity parameters of pyridinium ylides and their use in mechanistic analyses
-
Kinetics of the reactions of pyridinium, isoquinolinium, and quinolinium ylides with diarylcarbenium ions, quinone methides, and arylidene malonates (reference electrophiles) have been studied in dimethylsulfoxide solution by UV-vis spectroscopy. The seco
- Allg?uer, Dominik S.,Mayer, Peter,Mayr, Herbert
-
supporting information
p. 15216 - 15224
(2013/11/06)
-