We learned about hydrogenation when we first checked out addition reactions, but we were doing that with alkenes. Functionalization of porous silicon with alkenes and. Here, we report highly versatile cobaltcatalyzed hydrosilylations of alkynes that operate with minute amounts of the inexpensive, benchstable precatalyst cooac24h2o under mild con. Advanced proprietary platinum nheterocyclic carbene catalysts for hydrosilylation applications in both silicone and fine chemical industries. Hydrosilylation has been called the most important application. Hydrofunctionalizations of unsaturated hydrocarbons are key strategies for the synthesis of functionalized building blocks. Additions are the most common reactions using alkenes and alkynes addition to. Terminal alkynes afford access to alphavinylsilane products with good regioselectivity. Hydrosilylation of internal alkynes catalyzed by tris. In the reaction, pt catalysts, such as speiers catalysts h 2 ptcl 6 6h 2 o in iproh and karstedts catalyst, are widely used in the silicon industry as well as in laboratoryscale experiments. Hydrosilylation of alkynes catalysed by platinum on titania. Pdf an effective hydrosilylation of alkynes in supercritical co 2. This finding is noteworthy as a means of accessing. Platinum chloridexphoscatalyzed regioselective hydrosilylation of functionalized terminal arylalkynes.
Methods for hydrosilylation of terminal alkynes were developed some time ago, particularly for the preparation of cis and trans. Hydrosilylation is the definitive monograph in the area written for reseachers and industrial chemists involved in silicon chemistry, organic synthetic chemists with an interest in silicones, silane coupling agents and hybrid inorganicorganic materials. Ordinarily the reaction is conducted catalytically and usually the substrates are unsaturated organic compounds. Other reactions associated with alkyne hydrosilylation. We offer tailormade umicore hs catalysts for your most efficient hydrosilylation step. Iridiumcatalyzed markovnikov hydrosilylation of terminal alkynes. The reaction is tolerant to a wide range of functional groups including halogens, free alcohols, alkenes, internal alkynes, esters, and. To date, numerous studies have been performed in this field.
Iron catalysts for selective antimarkovnikov alkene. The same complex is active in internal alkyne hydrosilylation, where absolute selectivity for the trans addition process is maintained. Many regio and stereoselective modifications of related reactions are known. Hydrosilylation reactions of functionalized alkenes. Hydrosilylation of alkynes catalyzed by ruthenium carbene. Asymmetric hydrosilylation of prochiral ketones, imines and imine n. Recent advances in the hydrosilylation of alkynes scientific. It has since been found that hydrosilylation of a variety of alkenes and alkynes upon porous silicon is achieved in the presence of carbocation salts figure 1 6. An example of specific selectivity is in platinum catalized hydrosilylation.
Hydrosilylation of terminal alkynes with a variety of silanes catalyzed by cl2pcy32ruchph 1 affords mainly the zisomer via trans addition in excellent yields. Hydrosilylation reaction of alkenes is one of the most powerful methods to synthesize organosilicon compounds. The first highly efficient ligandcontrolled regio and stereodivergent intermolecular hydrosilylations of internal alkynes have been disclosed. Reaction in which halogen is introduced into a molecule 3 hydration.
The reaction is tolerant to a wide range of functional groups including halogens, free alcohols, alkenes, internal alkynes, esters, and amines. Rutheniumcatalyzed hydrosilylation of 1alkynes with. Hydrosilylation of aliphatic terminal alkynes a cobaltcatalyzed sequential highly enantioselective double hydrosilylation of aliphatic alkynes for the precise synthesis of chiralgembissilylalkanes was achieved. Coiadpph3ch2tms 1 iad 1,3diadamantylimidazol2ylidene facilitates regio and stereoselective hydrosilylation of terminal, symmetrical internal, and trimethylsilylsubstituted unsymmetrical internal alkynes to produce. Dehydrogenative silylation, related to the above process, is also discussed.
Pdf hydrosilylation of alkynes catalysed by platinum on. Chapter 1 presents a comprehensive survey of literature on hydrosilylation of alkenes and their derivatives by molecular compounds containing sih bond, published in the last two decades. Complex 1 proved an efficient catalyst for hydrosilylation of alkynes. Samariumii monoalkyl complex supported by a diketiminato. 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. Ligandcontrolled remarkable regio and stereodivergence. A new method for the hydrosilylation of alkynes controlled by a platinum catalyst with a monophosphine ligand called tbso. Pdf platinum chloridexphoscatalyzed regioselective. Coiadpph3ch2tms 1 iad 1,3diadamantylimidazol2ylidene facilitates regio and stereoselective hydrosilylation of terminal, symmetrical internal, and trimethylsilylsubstituted unsymmetrical internal alkynes to.
Buriak department of chemistry, 93 brown laboratories, purdue university, west lafayette, indiana 4790793 received october 30, 2001. Platinum complexes with chelating acyclic aminocarbene. Documented herein are the benefits of a versatile regiodivergent and stereoselective hydrosilylation of alkynes in the presence of only 0. Radical hydrosilylation of alkynes catalyzed by eosin y. Hydrosilylation of alkynes mediated by nheterocyclic carbene platinum0 complexes. This protocol used relatively simple and available starting materials to construct more valuable products with excellent chemo, regio and enantioselectivities. Pdf hydrosilylation of a wide group of alkynes terminal and internal with four structurally different silanes has been for the first time. A threecoordinate cobalti complex exhibits high catalytic efficiency and selectivity as well as good functional group compatibility in alkyne hydrosilylation.
Hydrosilylation of alkynes catalysed by platinum on titania rua. Hydrosilylation of alkynes using cycloalkenes as catalyst modifiers. Using two different hydrosilylation methods, low temperature thermal and uv initiation, silicon 111 hydrogenated surfaces were functionalized in presence of an ohterminated alkyne, a cf3. The corresponding alkenylsilanes were provided with high regio and stereoselectivites in the reactions of various terminal and internal alkynes. A general mechanistic overview of hydrosilylation is provided along with.
The hydrosilylation of alkynes using 2pyme2sih proceeded with a ptch2chsime22optbu3 catalyst to give alkenyldimethyl2pyridylsilanes in good yield with high regioselectivity. The nheterocycliccarbeneligated ruthenium complex ruhclcoh2imespcy3 exhibits high catalytic activity for the zselective hydrosilylation of various terminal alkynes with 1,1,1,3,5,5,5heptamethyltrisiloxane hsimeosime32. Pdf regiocontrol in the cobaltcatalyzed hydrosilylation. This work describes the preparation of a series of platinumaminocarbene complexes ptclcncac6r2r3r4r5conbnhr1cnr1ab 819, 6575% isolated yield via the reaction of cisptcl2cnr12 r1 cy 1, tbu 2, xyl 3, 2cl6mec6h3 4 with 3iminoisoindolin1ones hncac6r2r3r4r5conbh r2r5 h 5. The main preparative reactions involve the elimination of groups or ions from molecules, resulting in the formation of. For decades, precious metals, principally compounds of platinum and rhodium, have been used as catalysts for this.
A reactivity comparison of 2pyme2sih with other related hydrosilanes 3pyme2sih, 4pyme2sih, and phme2sih was also performed. To access a cheminform abstract, please click on html or pdf. Typical procedure for pd1cu2sio2 catalyzed regio and stereoselective hydrosilylation of alkynes. In terminal alkynes, cis addition of hydrosilane gives the eproduct while trans addition gives the zproduct. The method can be applied to the hydrosilylation of 1,4enynes con. Alkyne hydrosilylation catalyzed by a cationic ruthenium complex.
Hydride abstraction initiated hydrosilylation of terminal alkenes and alkynes on porous silicon j. Alkene hydrosilylation, the addition of a silicon hydride sih across a carboncarbon double bond, is one of the largestscale industrial applications of homogeneous catalysis and is used in the commercial production of numerous consumer goods. Eselective hydrosilylation of terminal alkynes by cobalt. Zselective hydrosilylation of terminal alkynes with.
Alkyne hydrosilylation catalyzed by a cationic ruthenium. Recent advances in the hydrosilylation and related reactions. Abstract the design and development of highly efficient and selective methods for the synthesis of alkenylsilanes, based on alkyne hydrosilylation, have been. Additionally, intramolecular variants have raised new questions regarding the mechanism of trans hydrosilylation of alkynes. Highly regioselective silylcupration of terminal alkynes reported by loh is.
Deuterium labeling studies indicate a clean trans addition process is at work. Hydrosilylation reactions of alkynes catalyzed by palladium nitrate. The stereoretentive derivatization of the zalkenylsiloxanes allows the synthesis of biologically active compounds, e. Hydrosilylation of internal alkynes catalyzed by trisa wiley online. Hydrosilylation of terminal alkynes occurs at or below room temperature catalyzed by the ruthenium complex 6 to afford the 1,1disubstituted. Hydrosilylation of alkynes catalysed by platinum on titania core. Markovnikov hydrosilylation of terminal alkynes catalyzed by a cobalt diphosphine complex.
Iridiumcatalyzed markovnikov hydrosilylation of terminal. The preparations of alkynes are very similar to those of the alkenes. 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. The experimental evidence shows that the reaction is. A diverse set of terminal alkynes underwent rapid and mild hydrosilylation in the presence of cprumecn 3pf 6 to give 1,1disubstituted. Reaction in which the elements of water h and oh are. Regio and stereoselective hydrosilylation of alkynes. The design and development of highly efficient and selective methods for the synthesis of alkenylsilanes, based on alkyne hydrosilylation, have been the subjects of extensive study, because of their versatile application in organic synthesis and material science. A cobaltcatalyzed zselective hydrosilylation of alkynes has been developed relying on catalysts generated from benchstable cooac2 and pyridine2,6diimine pdi ligands. Cobaltcatalyzed asymmetric synthesis of gembissilyl.
The most thermodynamically stable and usually major reaction product is the. A cobaltcatalyzed sequential highly enantioselective double hydrosilylation of aliphatic alkynes for the precise synthesis of chiral gembissilylalkanes was achieved. Regio and stereoselective hydrosilylation of alkynes catalyzed by. The hydrosilylation of disubstituted alkynes using platinum catalysts is slower than the hydrosilylation of monosubstituted alkynes but exhibits similar selectivities. The final outcome of the reaction depends on the catalyst, the alkyne, and the silane employed. Hydrosilylation catalyst in chemical synthesis sigmaaldrich. Cocl 2 was selected, and resulted in the corresponding vinylsilanes with high markovnikov regioselectivity and extensive functional. A visible lightpromoted hydrosilylation of alkynes has been explored and achieved using 1 mol % organic dye eosin y as the photocatalyst and a catalytic amount of thiol as the radical quencher. Hydrosilylation, also called catalytic hydrosilation, describes the addition of sih bonds across unsaturated bonds. The catalytic hydrosilylation reaction of terminal alkynes with hydrosilanes proceeds in high yields as well as with eselectivity by using a cobaltdiphosphine complex. The loss of a hydrogen atom and a halogen atom from adjacent alkane carbon atoms leads to the formation of an alkene. Among the different catalysts, platinum catalysts are usually. Hydride abstraction initiated hydrosilylation of terminal. Metalcatalyzed hydrosilylation of alkenes and alkynes.
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