Cucurbit[7]uril Promoting Pd-catalyzed Suzuki Cross-coupling Reaction Of Benzyl Chlorides And Arylboronic Acids

Diarylmethane derivatives are one of the most important building blocks inorganic synthesis and drug discovery research. The palladium-catalyzed Suzuki-Miyaura cross-coupling reaction has become a particularly attractive method to obtaindiarylmethane derivatives due to its mild condition, low cost, high efficiency. In thispaper we focus on the PdCl2-catalyzed Suzuki-Miyaura cross-coupling reaction ofbenzyl chlorides and arylboronic acids which was promoted by cucurbit[7]uril inaqueous media.1. The effect of cucurbit[n]uril on the Suzuki-Miyaura cross-coupling reactionThrough studying the role of cucurbit[n]uril played in the Suzuki-Miyauracross-coupling reaction between benzyl chlorides and arylboronic acids, wedeveloped a new catalytic system of PdCl2/CB[7]/NaCl.2. The Suzuki cross-coupling reaction of benzyl chlorides with arylboronic acidsAfter investigating carefully on the reaction conditions of solvent, base,temperature and time, we found that the Suzuki-Miyaura cross-coupling reactionbetween arylboronic acids and benzyl chlorides can be carried out under theconditions with EtOH/H2O (5:1) as solvent, K2CO3as base. Under this optimizedprocess condition, a series of diarylmethane derivatives were obtained in moderate tohigh yields (Scheme1).Scheme1The reaction of arylboronic with benzyl halides...