Reaction of Alkynes

Deprotonate terminal alkyne w/…

strong base (like NaNH2 or NaH)

To extend a alkyne (make a new c-c bond)

use Sn2 & an alkyl halide

Prepare alkynes by elimination

double dehydrohalogenation (E2 X 2)

Hydrogenation

reduction (H2, Pt or Pd) (H2, Lindlar) (Na, NH3, -78)

Hydration

Add water across triple bond; makes unstable enol; tautomerizes to ketone (markovnikov) or aldehyde (anti)

Markovnikov Hydration

H2O, H2SO4, Hg(OAc)2

Anti-Markovnikov Hydration

hydroboration-oxidation (BH3, R2BH, or (sia)2BH) & H2O2 & -OH

Alkyne Hydrohalogenation

1 equivalent HX makes markovnikov alkene (H-Br) & 2 equiv. HX makes geminal dihalide (xs H-Br)

Alkyne Halogenation

1 equiv. X₂ makes dihaloalkene (Br₂) & 2 equiv. X₂ makes tetrahaloalkane (xs Br₂)