Vinylchromium compounds

Vinylchromium compounds (12,137).6 These compounds can be obtained by reaction of vinyl triflates with CrCl2 catalyzed by NiCl2 in DMF. They undergo selective Grignard-type addition to aldehydes. Some commercial sources of CrCl2 do not require a catalyst, presumably because they contain a metal contaminant. 

Alkenylchromium compounds. Addition of CrCh to a vinyl iodide or bromide in DMF forms a vinylchromium compound that adds selectively to aldehydes to form an ally lie alcohol. CrCl, also effects addition of iodobenzene to aldehydes to form benzyl alcohols. 

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