Alkyne Electrophilic Addition

Atoms Added	Name	Reagents	Regiochemistry	Stereochemistry	Subsequent Reactions
B, H	Hydroboration	dicyclohexylborane	anti-Markovnikov	syn	Oxidation (H₂O₂, NaOH) Net anti-Markovnikov Addition of Water, Tautomerization of Enol to Aldehydes for Terminal Alkynes
H, H	Hydrogenation	hydrogen, transition metal	n/a	syn	double addition to make alkanes
H, H	Hydrogenation	hydrogen, transition metal, barium sulfate, quinoline (Lindlar Poison Catalyst)	n/a	syn	single addition to internal alkynes makes cis-alkenes
H, H	Sodium Reduction	sodium in ammonia	n/a	anti	single addition to internal alkynes makes trans-alkenes
Hg, O	Oxymercuration	Hg²⁺	Markovnikov?	anti	Demercuration with NaBH₄ or hydronium workup, Net Markovnikov Addition of Water, Tautomerization of Enol to Methyl Ketone for Terminal Alkynes
H, X	Hydrohalogenation	mineral acid	Markovnikov	n/a	double addition to make gem-dihalides
Br^., H^.	Bromine Radical Addition	hydrogen bromide, peroxide	anti-Markovnikov	n/a	n/a
X, X	Halogenation	halogen	n/a	anti	double addition to make tetrahalides