Properties of alkenes and alkynes no rotation around double and triple bonds similar to alkanes bp and mp isomerism cis and trans. Title regioselective transformation of alkynes catalyzed. The loss of a hydrogen atom and a halogen atom from adjacent alkane carbon atoms leads to the formation of an alkene. Acetylene itself is formed from the reaction of the inorganic compound calcium carbide with water. You will then learn the major reactions that alkynes undergo. The uses of ethyne, the first member of alkynes are listed below. Palladiumcatalyzed hydrocarboxylation of alkynes with formic acid. The catalytic activity can be significantly increased by the addition of catalytic amounts of bc 6 f 5 3. Alkynes are hydrocarboxylated with formic acid in the presence of catalytic amounts of pd. Pdf here we present an example of applying hydrogen bonding for regioselectivity control in addition. This method was once an important industrial process for the manufacture of acetylene. Mild, regiospecif ic hydrocarboxylation of alkynes catalyzed by. Dmacc instructional programming and administrative services have moved online. Yugen zhang and siti nurhanna riduan carbon dioxide homogeneous.
Title regioselective transformation of alkynes catalyzed by a copper. A facile, highly stereo and regioselective hydrometalation of alkynes generating alkenylmetal complex is disclosed for the first time from a reaction of alkyne, carboxylic acid, and a zerovalent group 10 transition metal complex mpet34 m ni, pd, pt. Highly efficient goldicatalyzed regio and stereoselective. Physical properties nonpolar and insoluble in water as are alkanes. Hydrocarboxylation of alkynes with carboxylic acids is an atom economical way to synthesize vinyl and alkenyl esters, some of which are industrially important compounds. If you have four different substituents around a double bond cistrans does not work e z nomenclature. The hydrocarboxylation and hydrosilylation processes proposed in the coppercatalyzed reaction among carbon dioxide, diphenylacetylene and hsioet 3 were comparatively studied with the aid of density functional theory calculations. The semihydrogenation, hydrocarboxylation, and hydroboration of alkynes have been developed using cuh as the active species. The reaction is tolerant to a wide range of functional groups including halogens, free alcohols, alkenes, internal alkynes, esters, and amines.
Cobaltcatalyzed carboxyzincation reactions employing carbon dioxide and zinc metal powder are developed. Structure of alkynes the functional group of an alkyne is a carboncarbon triple bond. Pdf cp 2 ticl 2 catalyzed hydrocarboxylation of alkynes with co. Catalytic hydrocarboxylation of alkenes and alkynes with co 2. Reaction of an alkyne with a hydrogen halide, leading to formation of a halogenated alkene or alkane.
To the best of our knowledge, no report of a highly e. A mechanistic study showed that the hydrometalation does not proceed via the reaction of alkyne with a hydridometal generated by the. Methods of preparation of alkynes by dehydrohalogenation. This research was supported by the institute of bioengineering and nanotechnology biomedical research council, agency for science, technology and research, singapore. Article views are the countercompliant sum of full text article downloads since november 2008 both pdf and html across all institutions and individuals. Catalyzed hydrocarboxylation of alkynes with formic acid. In this lesson, you will learn the types of alkynes and related functional groups.
Hydrocarbons can be monounsaturated one unsaturation or polyunsaturated more than one unsaturation. In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carboncarbon triple bond. A mild and userfriendly nicatalyzed regioselective hydrocarboxylation of alkynes with co 2 1 bar is described. Alkynes are hydrocarbons with carboncarbon triple bonds. Chapter 5 describes about ninhc catalyst development towards stereoselective semihydrogenation of alkynes by usig simple alcohol, isopropanol as. Nicatalyzed regioselective hydrocarboxylation of alkynes. These metrics are regularly updated to reflect usage leading up to the last few days. For the oxidative carbonylation of alkenes, palladium complexes are used. Catalytic boracarboxylation of alkynes with diborane and. Regioselective transformation of alkynes catalyzed by a copper. Catalytic hydrocarboxylation of alkenes and alkynes with.
But the alkenes obtained from the addition of an electrophilic reagent to an alkyne have at least one electronegative. This protocol is characterized by a wide scope while obviating the need for sensitive organometallic species and by an unprecedented regioselectivity pattern using simple alcohols as proton sources. S1 cp2ticl2catalyzed hydrocarboxylation of alkynes with co2. The antimarkovnikov hydrocarboxylation of substituted. Mild, regiospecif ic hydrocarboxylation of alkynes catalyzed by nickel cyanide. Journal of the american chemical society 2015, 7 28, 89248927.
Cf3c6h432o2cph2 is demonstrated to be a highly efficient catalyst in the challenging hydrocarboxylation of internal alkynes. Hydroxy groupenabled highly regio and stereoselective hydrocarboxylation of alkynes chaofan huang,a hui qian,a wanli zhanga and shengming ma ab here we present an example of utilizing hydroxy groups for regioselectivity control in the addition reaction. The oxidative carbonylation of methanol is catalyzed by copperi salts, which form transient carbonyl complexes. Alkynes are hydrocarbons, which are organic chemical compounds containing carbon c and hydrogen h atoms, and the feature that makes them recognized as alkynes is the presence of triple bonds. Each unsaturation in a compound reduces the number of hydrogen atoms in the molecular formula by 2.
The corresponding alkenylzinc moiety can be converted to various substituents, affording multisubstituted acrylic acids. The simplest acyclic alkynes with only one triple bond and no other functional groups form a homologous series with the general chemical formula c n h 2n. Hayashi1d and thomas1e have also independently reported the iron. Properties of alkenes and alkynes chemical properties undergo combustion as do alkanes. The preparations of alkynes are very similar to those of the alkenes. By using alkynes as substrates, regio and stereodefined z. A diverse set of terminal alkynes underwent rapid and mild hydrosilylation in the presence of cprumecn 3pf 6 to give 1,1disubstituted avinylsilanes in good to excellent yield, often with low catalyst loadings scheme 2, table 1.
This group of compounds is a homologous series with the general molecular formula of c n h 2 n2, where n equals any integer greater than one. Oac and suitable phosphine ligands 120 psi of co gas pressure. A protocol for nickelcatalyzed hydrocarboxylation of alkynes with formic acid was developed. The main preparative reactions involve the elimination of groups or ions from molecules, resulting in the formation of. Our study is to explore why the reaction preferred a hydrocarboxylation rather than a hydrosilylation process. Because the reported routes of hydrocarboxylation use other substrates, such as alkenes, alkynes, arenes andor organic halides, and the metallic reducing agents are. Roscher, ullmanns encyclopedia of industrial chemistry, wiley vch, weinheim, 2002. Carboxyzincation employing carbon dioxide and zinc powder. To gain insights into the reaction mechanism, fundamental catalytic steps in the hydrocarboxylation utilizing silanes were. The method provides acrylic acid and derivatives in good yields with high regioselectivity without the need to handle toxic co gas. Alkynes are traditionally known as acetylenes, although the name acetylene also refers specifically to c 2 h 2, known. Simple alkynes are named much like alkenes, except the ending is changed fromane toyne. Internal alkynes are compounds in which the triple bond is between two carbon atoms, none of which are terminal.
Some of the important methods of preparation of alkynes are. In praxis, the reaction is carried out with moderately strong bases, e. All reactions feature excellent stereoselectivities and good regioselectivities. Synthesis of acetic acid via methanol hydrocarboxylation. Reactions of alkynes jacquie richardson, cu boulder last updated 1152019 3 for the noperoxides reaction, markovnikovs rule is reinforced by the fact that not only is the carbocation stabilized by more rgroup substituents, its also stabilized by the first br to get added. Different energy and geometry changes may be required for additions to an alkyne and an alkene so some surprising outcomes may occur with alkynes. A mild and userfriendly nicatalyzed regioselective hydrocarboxylation of alkynes with co2 1 bar is described. Pdf hydroxy groupenabled highly regio and stereoselective. The application of the highly efficient ruthenium catalyst ruco 2 pp. In 2011, the group of ma described a nickelcatalyzed hydrocarboxylation of alkynes using nicod2 and diethylzinc as. Yi zhaoa,c, yuxia liub, siwei bib, yongjun liua, anorthwest institute of plateau biology, chinese academy of sciences, xining, qinghai 81, china b school of chemistry and chemical engineering, qufu normal university, qufu 273165, pr china. Nonpolar, therefore boiling points depend on size and shape. Ethyne is used as the basic material for making many other organic compounds such as ethanoic acid, ethanal, acrylic acid, etc.
Nickelcatalyzed hydrocarboxylation of alkynes with formic. The general molecular formula of alkynes is c n h 2n2. Calcium carbide is prepared by heating quicklime with coke. In further to examine the scope of hydrocarboxylation of alkynes, unsymmetrical internal alkynes were selected as substrates, and the representative results are shown in table 2. Nheterocyclic carbene coppercatalyzed carboxylation of. Physical properties of alkynes are very similar to the physical properties of alkenes. Unsaturated carboxylic acids china cp2ticl2catalyzed. Citations are the number of other articles citing this article, calculated by crossref and updated daily. Catalyzed hydrocarboxylation of alkynes with formic acid, angewandte chemie international edition on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Facile regio and stereoselective hydrometalation of.
Note that if a terminal alkyne is produced, the strong base will deprotonate the alkyne to form an alkynide anion. Pdf cp2ticl2catalyzed hydrocarboxylation of alkynes with co2 atmospheric pressure has been reported. Catalytic hydrocarboxylation of alkenes and alkynes with co2. Theoretical study on coppercatalyzed reaction of hydrosilane, alkyne and carbon dioxide. Dmacc facilities are not open for classes or to the public. Nicatalyzed regioselective hydrocarboxylation of alkynes with co2 by using simple alcohols as proton sources. Catalyzed reactions of alkynes in water request pdf. A proton source like h2o must be added to regenerate the terminal alkyne. Hydroxy groupenabled highly regio and stereoselective.
Furthermore, by adding electrondeficient alkene to the reaction system. Read suppression of hydride elimination in the intramolecular hydrocarboxylation of alkynes leading to the formation of lactones. Alkynes belong to the family of unsaturated hydrocarbons that is. Many regio and stereoselective modifications of related reactions are known. In contrast, the formal analogous addition of ammonia or primary and secondary amines to nonactivated alkenes and alkynes scheme 1. View enhanced pdf access article on wiley online library html view download pdf for offline viewing.
Number the chain from the end closest to the triple bond. Hydrocarboxylation of unactivated internal alkynes with. The regioselectivity is dictated by electronic and steric aspects of the alkyne substituents and the acidity of the carboxylic acid. A highly efficient and selective access to enol esters motivation references and acknowledgements 1 g. Since highersubstituted alkyl alkynes internal alkynes are more stable than terminal alkynes hyperconjugation, isomerization is favored thermodynamically. The simplest alkyne, ethyne also known as acetylene, has two carbon atoms and the. Alkynes are one of the simplest hydrocarbons known to us. Ethyne is prepared on large scale by the reaction of water on calcium carbide. Physical properties of alkynes chemical properties alkynes. Alkynes are used in the preparation of many other compounds. The protocol allowed for highly efficient synthesis of acrylic acid with a ton of up to 7700. Cp2ticl2catalyzed hydrocarboxylation of alkynes with co2.