Hydroborationoxidation of alkynes video khan academy. Atomefficient organoactinidecatalyzed intermolecular hydrothiolation of terminal alkynes is achieved by thiv and uiv complexes to yield vinyl sulfides. Regio and stereoselective synthesis of vinyl sulfides via. The reaction is highly selective and has a wide substrate scope. Catalystfree hydrothiolation of alkynes with dithiocarbamic. Here we report a cesiumcatalyzed hydrothiolation of alkynes. In contrast, the formal analogous addition of ammonia or primary and secondary amines to nonactivated alkenes and alkynes scheme 1 does not have comparable significance. With regard to the mechanism of hydrothiolation of terminal alkynes in water, the literature reports are of different views. Stereoselective hydrothiolation of alkynes catalyzed by cesium base. Avelino corma, camino gonzalezarellano, marta iglesias and felix sanchez, efficient synthesis of vinyl and alkyl sulfides via hydrothiolation of alkynes and electrondeficient olefins using soluble and heterogenized gold complexes catalysts, applied catalysis a. Pdf highly stereoselective antimarkovnikov hydrothiolation. Alkynes can have multiple reaction partners, such as other alkynes, alkenes, allenes, and c arbonylimine systems for the cycloisomerization leading to a variety of different carbocycles and heterocycles. Apr 30, 2014 in sharp contrast to many examples of transitionmetalcatalyzed hydrothiolation of alkynes, the corresponding catalytic addition of thiols to alkenes has remained undeveloped. A simple and efficient method for palladium and copper cocatalyzed markovnikov hydrothiolation of thiols to olefins or alkynes has been developed.
Design of a nihcatalyzed remote hydrothiolation reaction. Calciumcatalyzed bishydrothiolation of unactivated. Pdf onwater hydrothiolation reaction between terminal alkyne and thiol has been probed in the presence of various additives. In this manuscript, flowerlike microspheres of znin2s4 consisting of interweaving nanoflakes were prepared by a solvothe. The loss of a hydrogen atom and a halogen atom from adjacent alkane carbon atoms leads to the formation of an alkene. Aromatic alkynes yield corresponding alk enyl sul des, wher eas aliphatic alkynes undergo doubleaddition yielding vicinal disul des in good to excellent yields. A highly regio and stereocontrolled procedure for the synthesis of vinyl dithiocarbamates via catalystfree hydrothiolation of unactivated alkynes with in situ prepared dithiocarbamic acids with total atom economy is reported. In this manuscript, flowerlike microspheres of znin 2 s 4 consisting of interweaving nanoflakes were prepared by a solvothermal method and were applied for the first time in the visible light initiated hydrothiolation of alkenes and alkynes. Department of material chemistry, graduate school of engineering, kyoto university, kyotodaigaku katsura, nishikyoku, kyoto 6158510, japan.
Stereoselective hydrothiolation of alkynes catalyzed by. Hydrothiolation of alkenes and alkynes catalyzed by 3,4. Twostep reaction in which an alkene is converted to an alkene with a hydroxyl substituent which may tauromerize to a carbonyl. Number the chain from the end closest to the triple bond. The main preparative reactions involve the elimination of groups or ions from molecules, resulting in the formation of. Pdf catalytic alkyne hydrothiolation with alkanethiols. Catalysed hydrofunctionalisation of alkenes and alkynes. Regio and stereoselective synthesis of vinyl sulfides via phsebrcatalyzed hydrothiolation of alkynes.
Aromatic alkynes yield corresponding 1alkenyl sulfides, whereas aliphatic alkynes undergo doubleaddition yielding vicinal disulfides in good to excellent yields. Among hydrocarbons, alkynes have higher boiling point than alkenes and alkanes because of the presence of triple bond in alkynes. Recent advances in the hydrosilylation of alkynes emily a. Generally, it was found that alkyne and thiol derivatives were excellent reaction partners, producing the corresponding products with good yields and. Scribd is the worlds largest social reading and publishing site.
Note that if a terminal alkyne is produced, the strong base will deprotonate the alkyne to form an alkynide anion. View the article pdf and any associated supplements and figures for a period of 48 hours. Apr 15, 2019 here, the authors show the synergistic combination of nihcatalysed alkene isomerization and subsequent thiolation to afford remote hydrothiolation products from alkenes or alkynes and thiols. Physical properties of alkynes organic chemistry tutorial. Abstract alkyne hydrothiolation that is, the addition of the sh bond of a. 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. The simplest alkyne, ethyne also known as acetylene, has two carbon atoms and the.
Nickelcatalysed selective migratory hydrothiolation of. Waterpromoted regioselective hydrothiolation of alkynes. Markovnikov adducts in excellent yields within only a few minutes at 120 c in the presence of only 0. Catalytic alkyne hydrothiolation with alkanethiols using wilkinsons catalyst. Stereoselective hydrothiolation of alkynes catalyzed by cesium. Visible light initiated hydrothiolation of alkenes and alkynes over znin 2 s 4 yuanyuan li, jingyu cai, mingming hao, zhaohui li research institute of photocatalysis, state key laboratory of photocatalysis on energy and environment, college of chemistry, fuzhou university, fuzhou 350116, p. Highly regio and stereocontrolled synthesis of vinyl sulfides via transitionmetalcatalyzed hydrothiolation of alkynes with thiols akiya ogawa, takuma ikeda, kouichi kimura, and toshikazu hirao contribution from the department of applied chemistry, faculty of engineering, osaka university, suita, osaka 5650871, japan received november 16, 1998. Aromatic alkynes yield corresponding 1alkenyl sulfides, whereas aliphatic. Jun, 2018 we learned about hydrogenation when we first checked out addition reactions, but we were doing that with alkenes. Markovnikov addition of thiols to unactivated alkenes and alkynes was demonstrated by using 3,4.
Regioselective hydrothiolation of alkenes bearing heteroatoms. Pdf in quest of stereoselective switch for onwater. Visible light initiated hydrothiolation of alkenes and. Highly regio and stereocontrolled synthesis of vinyl. Methods of preparation of alkynes by dehydrohalogenation of. Indiumiiicatalyzed substrate selective hydrothiolation. In sharp contrast to many examples of transitionmetalcatalyzed hydrothiolation of alkynes, the corresponding catalytic addition of thiols to alkenes has remained undeveloped. Alkynes are hydrocarbons with carboncarbon triple bonds. The reaction allows olefins or alkynes bearing various functional groups to react with different thiols, providing good to excellent yields of alkyl sulfides or vinyl sulfides.
Rhodiumcatalyzed hydrothiolation of alkynes with thiols for. Hydrothiolation using alkyl thiols proceeds with excellent regioselectivity, providing convenient access to branched alkyl vinyl sulfides, which are difficult to synthesize by other means. Onwater hydrothiolation reaction between terminal alkyne and thiol has been probed in the presence of various additives. Facile access to z1alkenyl sulfides azusa kondoh, kazuaki takami, hideki yorimitsu, and koichiro oshima. Alkyne hydrothiolation that is, the addition of the sh bond of a thiol. However, a novel pdcatalyzed addition of thiols to alkenes bearing a heteroatom, such as oxygen and nitrogen, is found to proceed under mild conditions to give the corresponding markovnikov adducts, regioselectively, in good yields. Acetylene itself is formed from the reaction of the inorganic compound calcium carbide with water. Alkynes hydrothiolation radical reactions click chemistry.
However, a novel pdcatalyzed addition of thiols to alkenes bearing a heteroatom, such as oxygen and nitrogen, is found to proceed under mild conditions to give the corresponding markovnikov adducts, regioselectively. The hydrothiolation of alkenes or alkynes with thiols, represents an attractive and atom economic approach for the formation of cs bonds. Indium iii catalyzed substrate selective hydrothiolation of terminal alkynes article in chemical communications 4833. Nickelcatalysed selective migratory hydrothiolation of alkenes and alkynes with thiols. Lewisacidic caoso 2 c 4 f 9 2 caonf 2 was synthesized for the first time and was shown to be an excellent catalyst for the transformation. Reaction in which the elements of water h and oh are. Highly stereoselective antimarkovnikov hydrothiolation of alkynes. Formation of 1alkenyl sulfides proceeds with a high degree of regioselectivity via antimarkovnikov addition. Organoactinidemediated hydrothiolation of terminal alkynes with. Herein, we describe a simple and inexpensive protocol for the hydrothiolation of alkynes. Under the optimized conditions, rhodiumcatalyzed hydrothiolation of terminal alkynes proceeds regio and stereoselectively to afford the corresponding vinyl sulfides via an antimarkovnikov and synaddition process. We report herein that tprhpph32 tp hydrotris 3,5dimethylpyrazolylborate is a highly active catalyst for alkyne hydrothiolation with alkyl and aryl thiols.
These were used to catalyse the hydrothiolation of alkynes with a range. While unactivated terminal alkynes afforded the markovnikov adducts with excellent regioselectivity. For example, bhadra and ranu 54, in their studies on waterpromoted. Radical and nucleophilic thiol addition across alkynes in an antimarkovni kov fashion is wellknown.
In quest of stereoselective switch for onwater hydrothiolation of. The preparations of alkynes are very similar to those of the alkenes. Jul 09, 2007 satisfactorily, all alkynes tested were effective, although moderate yields were observed in the aryl alkynes table 2, entries 79. Many regio and stereoselective modifications of related reactions are known. The conversion is highly markovnikov selective and is capable of utilizing aromatic, benzylic, and aliphatic thiols. Bishydrothiolation of alkynes providing antimarkovnikov dithioacetals is reported. This method was once an important industrial process for the manufacture of acetylene. Organoactinidemediated hydrothiolation of terminal. Reactions that employ alkynes as starting materials are synthetically versatile, since alkynes can be prepared by a variety of strategies, including sonogashira coupling, nucleophilic addition of metal acetylides 14, and homologation of carbonyl groups 15. Onepot hydrothiolationkumada coupling protocol has been developed.
Hydrothiolation of unactivated alkynes catalyzed by indium. Catalystfree hydrothiolation of alkynes with dithiocarbamic acids. Simple alkynes are named much like alkenes, except the ending is changed fromane toyne. Coppercatalyzed selective hydroamination reactions of alkynes. The resulting vinyl sulfides underwent nicatalyzed kumada cross coupling with grignard reagents.
Rhodiumcatalyzed alkyne hydrothiolation with aromatic and. In quest of stereoselective switch for onwater hydrothiolation of terminal alkynes using different additives and green synthesis of vicinal dithioethers. Different energy and geometry changes may be required for additions to an alkyne and an alkene so some surprising outcomes may occur with alkynes. Synthesis of 1,1disubstituted olefins via catalytic alkyne. Nickelcatalysed selective migratory hydrothiolation of alkenes and. Addition of thiols to alkynes is an efficient strategy for the synthesis of vinyl sulfides, which are valuable intermediates in synthetic organic chemistry for the. Palladium and copper cocatalyzed markovnikov hydrothiolation. Organic chemistry international hindawi publishing corporation. In this context, water extract of rice straw ash wersa has been proven to be a green, mild and efficient solvent for the preparation of vinyl thioethers. Research article in quest of stereoselective switch for on. Reaction in which halogen is introduced into a molecule 3 hydration.
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