AUTHOR=Zhang Tian-Shu , Hao Wen-Juan , Cai Pei-Jun , Li Guigen , Tu Shu-Jiang , Jiang Bo 

TITLE=Copper-Catalyzed Annulation–Cyanotrifluoromethylation of 1,6-Enynes Toward 1-Indanones via a Radical Process

JOURNAL=Frontiers in Chemistry

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.00234

DOI=10.3389/fchem.2020.00234

ISSN=2296-2646

ABSTRACT=<p>A new Cu(II)-catalyzed annulation–cyanotrifluoromethylation of 1,6-enynes with Togni's reagent and trimethylsilyl cyanide (TMSCN) has been established, enabling the direct construction of trifluoromethylated 1-indanones with an all-carbon quaternary center in good yields. This reaction was performed by using low-cost Cu(OTf)<sub>2</sub> as the catalyst and Togni's reagent as both the radical initiator and a CF<sub>3</sub> source, providing an efficient protocol for building up an 1-indanone framework with wide functional group compatibility. The reaction mechanism was proposed through a radical triggered addition/5-<italic>exo</italic>-<italic>dig</italic> cyclization/oxidation/nucleophilic cascade.</p>