Access to 3‐(2‐Oxoalkyl)‐azaspiro[4.5]trienones via Acid‐Triggered Oxidative Cascade Reaction through Alkenyl Peroxide Radical Intermediate

Chang‐sheng Wang (1) , Thierry Roisnel (1) , Pierre H. Dixneuf (1) , Jean-François Soulé (1)

1 ISCR - Institut des Sciences Chimiques de Rennes

Azaspiro[4.5]trienones bearing ketone side chains at the 3-position are prepared from N-alkyl-arylpropiolamides and ketones via oxidative 1,2-difunctionalization of alkynes. The cascade sequence starts with the generation of alkenyl peroxide intermediates, which are obtained by addition of tert-butyl hydroperoxide to ketones in presence of a catalytic amount of a strong acid. Then, the ketone radical adds to alkynes, followed by spirocyclization and dearomatization process. This method represents a new example of difunctionalization of alkynes with simultaneous formation of two carbon-carbon single bonds and one carbon-oxygen double bond in one step.

Keywords: Radical reaction; Cascade; Heterocycles; Ketones; Peroxides

Domains: Chemical Sciences; Catalysis

Chang‐sheng Wang, Thierry Roisnel, Pierre H. Dixneuf, Jean-François Soulé. Access to 3‐(2‐Oxoalkyl)‐azaspiro[4.5]trienones via Acid‐Triggered Oxidative Cascade Reaction through Alkenyl Peroxide Radical Intermediate. Advanced Synthesis and Catalysis, 2019, 360 (3), pp.1-7. ⟨10.1002/adsc.201801203⟩. ⟨hal-01954104⟩