BF<sub>3</sub>.OEt<sub>2</sub>-Mediated Benzylation of Arenes and Heteroarenes with Benzyl Ether Derivatives

Abstract

An efficient BF3•Et 2 O-promoted benzylation of arenes and heteroarenes with various benzyl ether derivatives has been developed. This method provided alternative access to valuable diarylmethane in good yields under mild conditions via an easy work-up procedure.

Radical-Friedel–Crafts benzylation of arenes with benzyl ethers over 2H-MoS2: ether cleavage into carbon- and oxygen-centered radicals

“…However, the acid MoO 3 (the BET is 3.5 m 2 g −1 ) showed no activity for this model reaction (entry 2), which is opposite to the traditional acid-promoted Friedel–Crafts reaction with benzyl alcohol as the benzylation reagent. 7,10,15,52 While some other reported Friedel–Crafts catalysts like homogeneous metal chlorides FeCl 3 , SnCl 4 , and AlCl 3 , trifluoromethanesulfonate Sc(OTf) 3 , and heterogeneous acid zeolites (MCM-41 and H-ZSM-5) could achieve the benzylation reaction between DBE and PX with different efficiencies (Table 1, entries 3–6 and entries 8 and 9), the Lewis acid catalyst Zn(OTf) 2 and typical acid zeolite H-beta cannot catalyze the model reaction (entries 7 and 10). The above preliminary results indicate that the character of the acid metal ion in the Lewis acid metal salts and the acidic character of the molecular sieve are critical for the performance of this catalytic reaction.…”