Alkyne

An alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond between two carbon atoms.

Quotes

• The characteristic hybridization scheme for the triple bond of an alkyne controls its physical and electronic features. It is responsible for strong bonds, the linear structure, and the relatively acidic alkynyl hydrogen. In addition, alkynes are highly energetic compounds. Internal isomers are more stable than terminal ones, as shown by the relative heats of hydrogenation.
  • K. Peter C. Vollhardt, Neil E. Schore (2011) Organic chemistry : structure and function 6th ed. Ch. 13 : Alkynes

• The cylindrical π cloud around the carbon – carbon triple bond induces local magnetic fields that lead to NMR chemical shifts for alkynyl hydrogens at higher fields than those of alkenyl protons. Long-range coupling is observed through the C≡C linkage. Infrared spectroscopy provides a useful complement to NMR data, displaying characteristic bands for the C≡C and ≡C–H bonds of terminal alkynes. In the mass spectrometer, alkynes fragment to give resonance-stabilized cations.
  • K. Peter C. Vollhardt, Neil E. Schore (2011) Organic chemistry : structure and function 6th ed. Ch. 13 : Alkynes

• Conversion of 1-alkynes into substituted actic acids without the loss of one carbon is accomplished via hydroboration-oxidation … Ruthenium- or permanganate-mediated oxidations of internal alkynes are highly dependent on solvent conditions and generally afford the corresponding α-diketones.
  • George S. Zweifel and Michael H. Nantz, Modern Organic Synthesis (2006), Ch. 4 : Functional Group Transformations: Oxidation and Reduction