Selective formation of dihydrofuran fused [60] fullerene derivatives by TEMPO mediated [3 + 2] cycloaddition of medium chain β-keto esters to C60

In this study, β-keto esters as readily available bio-based building blocks were used to decorate the C₆₀ sphere. Generally, cyclopropanated fullerene derivatives are obtained by the standard Bingel–Hirsch procedure. Herein, omitting the iodine from the reaction mixture and adding TEMPO afforded dihydrofuran fused C₆₀ fullerene derivatives. The mechanism of the reaction shifted from nucleophilic aliphatic substitution to oxidative [3 + 2] cycloaddition via fullerenyl cations as an intermediate. This mechanism is proposed based on a series of control experiments with radical scavengers. Therefore, dihydrofuran-fused C₆₀ derivatives were selectively obtained in good yields and their structures were established based on UV-Vis, IR, NMR spectroscopy and mass spectrometry. The electrochemical properties of the synthesized compounds were investigated by cyclic voltammetry. DFT calculations were performed in order to investigate the difference in stability, electronic properties and π-electron delocalization between methano and furano fullerenes.

In this study, β-keto esters as readily available bio-based building blocks were used to decorate the C₆₀ sphere.

Metal-free phosphonation of benzoxazoles and benzothiazoles under oxidative conditions

A metal-free C-2 phosphonation of benzoxazoles and benzothiazoles with trialkyl phosphites was described.

Copper-catalyzed tandem trifluoromethylation–cyclization of olefinic carbonyls: synthesis of trifluoromethylated 2,3-dihydrofurans and 3,4-dihydropyrans

A copper-catalyzed trifluoromethylation–cyclization of olefinic carbonyls was developed. With this method, a variety of 2,3-dihydrofuran and 3,4-dihydropyran derivatives containing a CF₃ group were selectively obtained in moderate to good yields.