Ethynyl group
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
[change | change source]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
[change | change source]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
[change | change source]- ↑ 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.