page_title: Vinyl iodide functional group
section_title: Other applications
hierarchical_section_title: Vinyl iodide functional group / Other applications
caption_attribution_description: English: Magnesium-halogen exchange
context_page_description: In organic chemistry, a vinyl iodide functional group is an alkene with one or more iodide substituents. Vinyl iodides are versatile molecules that serve as important building blocks and precursors in organic synthesis. They are commonly used in carbon-carbon forming reactions in transition-metal catalyzed cross-coupling reactions, such as Stille reaction, Heck reaction, Sonogashira coupling, and Suzuki coupling. Synthesis of well-defined geometry or complexity vinyl iodide is important in stereoselective synthesis of natural products and drugs.
context_section_description: Besides using vinyl iodides as useful substrates in transition metal cross-coupling reaction, they can also undergo elimination with a strong base to give corresponding alkyne, and they can be converted to suitable vinyl Grignard reagents. Vinyl iodides are converted to Grignard reagents by magnesium-halogen exchange (see Scheme 1a). The scope of this synthetic method is limited since it requires higher temperatures and longer reaction time, which affects functional group tolerance. However, vinyl iodide with electron withdrawing group can enhance rate of exchange(see Scheme 1b). Also addition of lithium chloride helps enhance magnesium-halogen exchange (see Scheme 1c). It is predicted lithium chloride breaks up aggregates in organomagnesium reagents.
caption: Scheme 1. Magnesium-halogen exchange
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