Direct intermolecular three-component aminotrifluoromethylation of styrenes by visible-light-photoredox catalysis

Abstract

Reported herein is a visible light photoredox-catalyzed intermolecular three-component aminotrifluoromethylation of styrenes with phenylhydrazines and Togni’s reagents/fluoroalkyl iodides. This synthetic strategy utilizes phenylhydrazines as nitrogen sources, and Togni’s reagent or...

Palladium–Copper-Catalyzed Oxidative Intermolecular [2 + 2 + 2] Coupling–Annulation: Regioselective Synthesis of Multiaryl-Substituted Benzenes

“…(Table 1, entries 18−19). The above results suggested that the reaction conditions of previous works 22,23 were not applicable in our reaction to construct multiaryl-substituted benzenes.…”

“…Control experiments indicated that a palladium catalyst, a copper salt, and an oxygen atmosphere are important for this coupling−annulation reaction (Table 1, entries 14 −17). However, the reactions of 1a with 2a under the reaction conditions according to the previous reports 22,23 resulted in a low yield of product 3a…”

“…22 Subsequently, they developed a palladium-catalyzed intermolecular carboesterification of 3-phenylpropiolates and alkenes to construct α-methylene-γ-lactone rings. 23 As a continuous effort in the development of a new synthetic strategy for direct C−C bond formation, 24 we disclose herein an efficient palladium-/copper-catalyzed oxidative intermolecular [2 + 2 + 2] coupling−annulation of terminal alkenes and alkynes for the preparation of various multiaryl-substituted benzenes (Scheme 2b). The features of this strategy are high regioselectivity, broad substrate scope, high atom and step economy, and ligand-free.…”

Electrochemical aminotrifluoromethylation of unactivated alkenes with Langlois’ reagent as the CF3 source

“…In recent decades, chemists have developed numerous efficient methods for synthesizing various trifluoromethyl-substituted amines and N-heterocycles by utilizing different nucleophilic and electrophilic CF 3 reagents. 2 Using a copper/Togni's reagent system, Liu, 3 Sodeoka, 4 and He 5 independently achieved an efficient intramolecular aminotrifluoromethylation of unactivated alkenes for the synthesis of various trifluoromethylated N-heterocycles (Scheme 1a). In addition, using equivalents of oxidants, other cheap and readily available trifluoromethyl reagents such as trifluoroacetic anhydride (TFAA), 6 (TMS)CF 3 , 7 and Langlois’ reagent 8 were also applied to the construction of diverse trifluoromethylated N-heterocycles (Scheme 1b).…”