and efficientasymmetric dearomative oxyalkylation of indoles with TEMPO oxoammonium salt and a variety of aldehydes and ketones has been described. This metal-free approach provides a straightforward access to C2 quaternary oxindoles in high yields with excellent diastereo- and enantioselectivities under very mild conditions. The reaction goes smoothly even with only 0.1% equivalent catalyst. Moreover
Concurrent Asymmetric Reactions Combining Photocatalysis and Enzyme Catalysis: Direct Enantioselective Synthesis of 2,2-Disubstituted Indol-3-ones from 2-Arylindoles
作者:Xuan Ding、Chun-Lin Dong、Zhi Guan、Yan-Hong He
DOI:10.1002/anie.201811085
日期:2019.1.2
The combination of photoredox and enzymatic catalysis for the direct asymmetric one‐potsynthesis of 2,2‐disubstituted indol‐3‐ones from 2‐arylindoles through concurrent oxidization and alkylation reactions is described. 2‐Arylindoles can be photocatalytically oxidized to 2‐arylindol‐3‐one with subsequent enantioselective alkylation with ketones catalyzed by wheat germ lipase (WGL). The chiral quaternary
PPh
<sub>3</sub>
‐Mediated Wittig‐Like/Mannich Tandem Reactions of 2‐Alkynylnitrobenzenes with Ketones for the Synthesis of 2,2‐Disubstituted Indolin‐3‐Ones
A synthetic strategy for the construction of 2,2-disubstituted indolin-3-ones from 2-alkynylnitroarenes and ketones has been described. The corresponding indolin-3-one derivatives were afforded in moderate to excellent product yields by using mild conditions. After a Wittig-like process, the key intermediates 3H-indol-3-ones were generated from 2-alkynylnitroarenes, which could be further transformed
Ru-Catalyzed Redox-Neutral Cleavage of the N–O Bond in Isoxazolidines: Isatogens to Pseudoindoxyls via a One-Pot [3 + 2]-Cycloaddition/N–O Cleavage
作者:Chepuri V. Suneel Kumar、Chepuri V. Ramana
DOI:10.1021/acs.orglett.5b00837
日期:2015.6.19
A novel metal-catalyzed oxygen atom transfer reaction onto olefins is reported. By taking isatogens as substrates, a one-pot [3 + 2]-cycloaddition of nitrone with olefins followed by the Ru-catalyzed redox-neutral N-O bond cleavage of intermediate isoxazolidine has been executed as a simple method for the synthesis of 2,2-disubstituted pseudoindoxyls.