hydrohalogenoinnin
Hydrohalogenation, or hydrohalogenoinnin in Finnish, is the electrophilic addition of hydrogen halides HX to unsaturated hydrocarbons, such as alkenes and alkynes. The reaction forms organohalogen compounds and is one of the most straightforward methods to convert alkenes into alkyl halides and alkynes into vinyl and dihalides.
For alkenes, the mechanism proceeds by protonation of the carbon–carbon double bond by HX to generate a
For alkynes, two equivalents of HX add across the triple bond to furnish dihalides; the first addition
Limitations include possible rearrangements for alkenes and the need to control over-addition, especially with reactive iodides