Synthesis of 1,2-Diarylethylenes by Pd-Catalyzed One-Pot Reaction of Benzyl Halides, Tosylhydrazide, and Aryl Aldehydes

Background: Substituted olefins are versatile functional groups and intermediates in chemistry, medicine, electronics, and optics and materials science fields because of their unique properties. One important class of substituted olefins 1,2-diarylethylenes have attracted considerable attention due to their presence in both natural products and pharmacologically active substances. Methods: In this paper, we developed a one-pot two-step coupling reaction of aryl aldehydes, tosylhydrazide with benzyl halides by using inexpensive Pd(PPh3)4 as catalyst, leading to a variety of 1,2- diphenylethenes derivatives with moderate to good yields. Results: The desired 1,2-diarylethylenes were obtained in 46-96% yields via Pd(0)-catalyzed one-pot reaction of benzyl halides, tosylhydrazide, and aryl aldehydes. Conclusion: The catalytic system presented here enables the use of easily accessible starting materials and good functional group tolerance.