Vinyl halide
In organic chemistry, a vinyl halide is a compound with the formula CH2=CHX (X = halide). The term vinyl is often used to describe any alkenyl group. For this reason, alkenyl halides with the formula RCH=CHX are sometimes called vinyl halides. From the perspective of applications, the dominant member of this class of compounds is vinyl chloride, which is produced on the scale of millions of tons per year as a precursor to polyvinyl chloride.[1] Polyvinyl fluoride is another commercial product. Related compounds include vinylidene chloride and vinylidene fluoride.
Synthesis
Vinyl chloride is produced by dehydrochlorination of 1,2-dichloroethane.[1]
A large number of reactions to form vinyl halides, which includes the reaction of vinyl organometallic species with halogens, and the Takai and Wittig olefination reactions. Olefin metathesis has also been shown to offer a distinct synthesis approach to access vinyl halides efficiently and stereoselectively.[2]
Reactions
Vinyl bromide and related alkenyl halides form the Grignard reagent and related organolithium reagents. Alkenyl halides undergo base elimination to give the corresponding alkyne. Most important is their use in cross-coupling reactions (e.g. Suzuki-Miyaura coupling, Stille coupling, Heck coupling, etc.).
References
- ^ a b E.-L. Dreher; T. R. Torkelson; K. K. Beutel (2011). "Chlorethanes and Chloroethylenes". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.o06_o01.
- ^ Koh, Ming Joo; Nguyen, Thach T.; Zhang, Hanmo; Schrock, Richard R.; Hoveyda, Amir H. "Direct synthesis of Z-alkenyl halides through catalytic cross-metathesis". Nature. 531 (7595): 459–465. Bibcode:2016Natur.531..459K. doi:10.1038/nature17396. PMC 4858352. PMID 27008965.
- ^ Nguyen, Thach T.; Koh, Ming Joo; Shen, Xiao; Romiti, Filippo; Schrock, Richard R.; Hoveyda, Amir H. (2016-04-29). "Kinetically controlled E-selective catalytic olefin metathesis". Science. 352 (6285): 569–575. Bibcode:2016Sci...352..569N. doi:10.1126/science.aaf4622. PMID 27126041.