Thiol-yne reaction
Encyclopedia
The Thiol-yne reaction is an organic reaction
between a thiol
and an alkyne
. The reaction product is an alkenyl sulfide. The reaction was first reported in 1949 with thioacetic acid
as reagent and rediscovered in 2009 It is used in click chemistry
and in polymerization
, especially with dendrimer
s.
This addition reaction
is typically facilitated by a radical initiator
or UV irradiation and proceeds through a sulfanyl radical species.With monoaddition a mixture of E/Z alkenes form. The mode of addition is anti-Markovnikov. The radical intermediate can engage in secondary reactions such as cyclisation. With diaddition the 1,2-disulfide or the 1,1- dithioacetal forms. Reported catalysts for radical additions are triethylborane
, indium(III) bromide and AIBN. The reaction is also reported to be catalysed by cationic rhodium
and iridium
complexes, by thorium
and uranium
complexes, by rhodium
complexes, by caesium carbonate
and by gold
.
Diphenyl disulphide reacts with alkynes to a 1,2-bis(phenylthio)ethylene. Reported alkynes are ynamides
, systems have been described based on addition polymerisation with 1,4-benzenedithiol and 1,4-diethynylbenzene, in the synthesis of dendrimer
s, in star polymers, in graft polymerisation, block copolymers and in polymer networks. Another reported application is the synthesis of macrocycles via dithiol coupling.
Organic reaction
Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions, photochemical reactions and redox reactions. In organic synthesis,...
between a thiol
Thiol
In organic chemistry, a thiol is an organosulfur compound that contains a carbon-bonded sulfhydryl group...
and an alkyne
Alkyne
Alkynes are hydrocarbons that have a triple bond between two carbon atoms, with the formula CnH2n-2. Alkynes are traditionally known as acetylenes, although the name acetylene also refers specifically to C2H2, known formally as ethyne using IUPAC nomenclature...
. The reaction product is an alkenyl sulfide. The reaction was first reported in 1949 with thioacetic acid
Thioacetic acid
Thioacetic acid is an organosulfur compound with the molecular formula CH3COSH. It is a colourless liquid with a strong thiol-like odor. It is used in organic synthesis for the introduction of thiol groups in molecules-Synthesis and properties:...
as reagent and rediscovered in 2009 It is used in click chemistry
Click chemistry
Click chemistry is a chemical philosophy introduced by K. Barry Sharpless of The Scripps Research Institute, in 2001 and describes chemistry tailored to generate substances quickly and reliably by joining small units together...
and in polymerization
Polymerization
In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains...
, especially with dendrimer
Dendrimer
Dendrimers are repetitively branched molecules. The name comes from the Greek word "δένδρον" , which translates to "tree". Synonymous terms for dendrimer include arborols and cascade molecules. However, dendrimer is currently the internationally accepted term. A dendrimer is typically symmetric...
s.
| Thiol-yne reaction |
|---|
This addition reaction
Addition reaction
An addition reaction, in organic chemistry, is in its simplest terms an organic reaction where two or more molecules combine to form a larger one....
is typically facilitated by a radical initiator
Radical initiator
In chemistry, radical initiators are substances that can produce radical species under mild conditions and promote radical reactions . These substances generally possess weak bonds—bonds that have small bond dissociation energies. Radical initiators are utilized in industrial processes such...
or UV irradiation and proceeds through a sulfanyl radical species.With monoaddition a mixture of E/Z alkenes form. The mode of addition is anti-Markovnikov. The radical intermediate can engage in secondary reactions such as cyclisation. With diaddition the 1,2-disulfide or the 1,1- dithioacetal forms. Reported catalysts for radical additions are triethylborane
Triethylborane
Triethylborane , also called triethylborine and triethylboron, is an organoborane , a near-colorless to yellowish transparent liquid with pungent ether-like odor. Its chemical formula can be written as C6H15B, or 3B, or 3B, or Et3B.Triethylborane is strongly pyrophoric, igniting spontaneously in...
, indium(III) bromide and AIBN. The reaction is also reported to be catalysed by cationic rhodium
Rhodium
Rhodium is a chemical element that is a rare, silvery-white, hard and chemically inert transition metal and a member of the platinum group. It has the chemical symbol Rh and atomic number 45. It is composed of only one isotope, 103Rh. Naturally occurring rhodium is found as the free metal, alloyed...
and iridium
Iridium
Iridium is the chemical element with atomic number 77, and is represented by the symbol Ir. A very hard, brittle, silvery-white transition metal of the platinum family, iridium is the second-densest element and is the most corrosion-resistant metal, even at temperatures as high as 2000 °C...
complexes, by thorium
Thorium
Thorium is a natural radioactive chemical element with the symbol Th and atomic number 90. It was discovered in 1828 and named after Thor, the Norse god of thunder....
and uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
complexes, by rhodium
Rhodium
Rhodium is a chemical element that is a rare, silvery-white, hard and chemically inert transition metal and a member of the platinum group. It has the chemical symbol Rh and atomic number 45. It is composed of only one isotope, 103Rh. Naturally occurring rhodium is found as the free metal, alloyed...
complexes, by caesium carbonate
Caesium carbonate
Caesium carbonate is a white crystalline solid of formula Cs2CO3. It is more soluble in organic solvents than many other carbonates such as potassium carbonate, and therefore finds use as a base in organic chemistry....
and by gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
.
| Ichinose et al. thiol-yne reaction 1987 |
|---|
Diphenyl disulphide reacts with alkynes to a 1,2-bis(phenylthio)ethylene. Reported alkynes are ynamides
Polymer chemistry
In polymer chemistryPolymer chemistry
Polymer chemistry or macromolecular chemistry is a multidisciplinary science that deals with the chemical synthesis and chemical properties of polymers or macromolecules. According to IUPAC recommendations, macromolecules refer to the individual molecular chains and are the domain of chemistry...
, systems have been described based on addition polymerisation with 1,4-benzenedithiol and 1,4-diethynylbenzene, in the synthesis of dendrimer
Dendrimer
Dendrimers are repetitively branched molecules. The name comes from the Greek word "δένδρον" , which translates to "tree". Synonymous terms for dendrimer include arborols and cascade molecules. However, dendrimer is currently the internationally accepted term. A dendrimer is typically symmetric...
s, in star polymers, in graft polymerisation, block copolymers and in polymer networks. Another reported application is the synthesis of macrocycles via dithiol coupling.