Alkyne Addition Reactions CHM 221

Acetylene Deprotonation

Uses NaNH2, any base who’s conj acid 25>

cis alkene/poisoned catalyst

lindlards catalyst, P-2

trans alkene/dissolving metal reduction

Na with NH3

Hydrohalogenation

Markovnikov, 1 eq puts one halogen with double bond, excess puts both with single bonds. HBr with ROOR still does anti markovnikov.

Acid Catalyzed Hydration

H2SO4 and water with HgSO4, forms enol (not isolated), then immediately forms ketone

Hydroboration Oxidation

Uses 9-BBN instead of BH3, also forms an anti markovnikov enol that immediately tautomerizes int can aldehyde

Markovnikov addition

ketone

Ant Markovnikov

aldehyde

Halogenation

1 eq of X2 yields double bond with 2 halogens, 2 eq of X2 yields a tetrahalides

Oznolysis

O3 with Water; on a terminal alkyne yields a carboxylic acid and carbon dioxide, on an internal alkyne yields 2 carboxylic acids

Alkylation of terminal alkynes

strong base (NaNH2, deprotonates alkyne), then alkyl halide. Will proceed via Sn2 rxn to add on the alkyl chain.