The ethynyl group, sometimes called ethinyl, is a functional group in organic chemistry. It is related to acetylene by replacing a hydrogen atom with a bigger molecule. It is the simplest alkyne-based group.
Preparation
Ethynyl compounds can be prepared by nucleophilic addition of acetylene (as its acetylide conjugate base, HC≡C−) to an electrophile. "Ethynylation" normally means addition to a carbonyl compound to make a propargylic ynol, or addition to a organohalide to make a non-terminal alkyne.[1]
Acid-base chemistry
Ethynyl groups are terminal alkynes. This makes them stronger acids than other hydrocarbon groups. Superbases like alkali metal hydrides or azides can deprotonate ethynyl compounds to give substituted acetylides, R−C≡C−. These carbanions are strong nucleophiles and react with many electrophiles to make internal alkyne compounds.[source?]
Sources
- ↑ Voronin, Vladimir V.; Ledovskaya, Maria S.; Bogachenkov, Alexander S.; Rodygin, Konstantin S.; Ananikov, Valentine P. (2018). "Acetylene in Organic Synthesis: Recent Progress and New Uses". Molecules. 23 (10): 2442. doi:10.3390/molecules23102442. PMC 6222752. PMID 30250005.