Palladium‐Catalysed Synthesis of α‐(Trifluoromethyl)styrenes by Means of Directed C–H Bond Functionalization

Abstract

We report the first introduction of 2‐bromo‐3,3,3‐trifluoropropene (BTP) by directed C–H bond functionalization. The developed method gives straightforward access to α‐(trifluoromethyl)styrene derivatives without prior prefunctionalization of the substrates. This palladium‐catalysed transformation was applied to a broad range of substrates, and the corresponding trifluoromethylated products were obtained in good yields. This approach represents an alternative pathway to the classical method previously used to access such molecules.

Synthesis of 4-Difluoromethylquinolines by NHC-Catalyzed Umpolung of Imines

“…Driven by our recent synthesis of indoles by NHC-catalyzed umpolung of imines, the present study was initiated by treating aldimine 1a with the carbene generated from bicyclic triazolium salt 3 using DBU as the base in DMF at 100 °C. To our delight, under these conditions the reaction afforded difluoromethylquinoline 2a in 75% yield (Table , entry 1).…”

Recent advances in transition-metal catalyzed directed C–H functionalization with fluorinated building blocks

“…[136][137][138][139][140] In this context, the directed C-H functionalization with BTP was realized by Bouillon and coworkers in 2016. 141 They developed a method to access α-(trifluoromethyl)styrene derivatives of anilides without prior prefunctionalization of the substrates through a Pd catalyzed C-H activation strategy. A broad range of anilide derivatives 135 were successfully coupled with BTP 136 to afford the desired α-(trifluoromethyl) styryl derivatives 137 in moderate to good yields (Scheme 28).…”

Palladium(II)-Catalyzed Oxidative Homo- and Cross-Coupling of Aryl ortho-sp2 C–H Bonds of Anilides at Room Temperature

“…white solid (3.04 g, 74% yield); mp 113–115 °C (lit . 121–122 °C); 1 H NMR (400 MHz, CDCl 3 ) δ 7.45 (t, J = 1.6 Hz, 1H), 7.30 (m, 2H), 7.23 (t, J = 7.8 Hz, 1H), 6.98–6.92 (m, 1H), 2.63 (q, J = 7.6 Hz, 2H), 1.32 (s, 9H), 1.23 (t, J = 7.6 Hz, 3H).…”