An orthogonality of the current catalytic protocol with those using a. Abstract ircodcl 2 is an effective precatalyst for the intramolecular hydroamination of a range of unactivated alkenes with pendant secondary amines. Intramolecular hydroamination of alkynes catalyzed by silverphenanthroline complexes doctoral dissertation. Goldicatalyzed intramolecular hydroamination of alkyne. Intramolecular hydroamination of internal alkyne with primary amine 11 yielding imine 12 and terminal alkyne with secondary amine yielding enamine 14 using the same samarium catalyst. Jan, 2006 read isoindoles and dihydroisoquinolines by gold. As for the c6d6 solvent, the intramolecular hydroamination reaction was.
An efficient and green approach to synthesizing enamines. The intramolecular hydroamination of alkynes tethered with amino group 1 in the presence. Silvercatalyzed intramolecular hydroamination of alkynes. Herein, we report a novel protocol that directly converted 22propynylaniline derivatives 1 into tetrahydroquino.
Mechanism, origin of enantioselectivity, and role of additives c. Frustrated lewis pairs flps based on sterically encumbered anilines and the lewis acid bc 6 f 5 3 were found to react with terminal alkynes effecting intermolecular hydroamination affording iminium alkynylborate species of the form rphn cr. Intramolecular addition of o h and nh bonds across carboncarbon triple bonds to form 5 or 6membered rings with exocyclic methylene groups for ether products and exocyclic methyl groups for imine products is catalyzed by iprcume ipr 1,3bis2,6diisopropylphenylimidazol2ylidene. Intramolecular copetype hydroamination of alkenes and alkynes using hydrazides. Some late transition metal complexes have been investigated for enantioselective hydroamination, with good results for alkynes, 8 allenes, 9 dienes, 10 and vinylarenes. Of these methods, the hydroamination of alkenes and alkynes, specifically the addition of an nh bond across a carboncarbon. The catalytic intermolecular hydroamination of alkynes is more difficult to accomplish than the intramolecular version, thus requiring higher tempera ture. Consecutive intramolecular hydroaminationasymmetric. In the hydroamination, unsaturated molecules including alkenes, alkynes, allenes. Hydroamination, the addition of hnr 2 across a carboncarbon. Hydrogenation and hydroamination reactions using boron. Department of chemistry, national university of singapore, 3 science drive 3, singapore 117543. Unlimited viewing of the articlechapter pdf and any associated supplements and figures. Intramolecular hydroamination of unactivated alkenes 31102006 2.
Silvercatalyzed intramolecular hydroamination of alkynes in aqueous media. Finally, the lewis acid bc 6f53 is found to enable the intermolecular hydroamination of various terminal alkynes giving iminium alkynylborate complexes of. Gold nanoclusters stabilized by a hydrophilic polymer, polynvinyl2pyrrolidone au. Andy horb and king kuok mimi hii,a department of chemistry, imperial college london, south kensington, london sw7 2az, u. Silvercatalysed intramolecular hydroamination of alkynes. In the synthetic process of the derivatives, n,ndimethylformamidedmf pretreated with metal na, was used. Silveri complexes catalyse the intramolecular addition of trichloroacetimidates to alkynes. The catalytic hydrogenation of the resulting enamines leads to substituted saturated azoles in good yields. Catalyzed intramolecular asymmetric hydroamination. Intramolecular hydroamination of unactivated alkenes with. Under 100, with cucl as catalyst, intermolecular and intramolecular double hydroamination reaction has generated between 1,3butadiyne and primary amine 24 scheme 27, 1,4two substituted 1,3butadiyne and alkynes through selective intermolecular hydroamination to form 1, 2, 5three substituted pyrroles with a high yield. Zeises dimercatalyzed regioselective hydration of homopropargyl tertiary ether. The catalytic hydrogenation of the resulting enamines leads.
Intramolecular hydroamination of alkynes catalyzed by pd. Silvercatalyzed intramolecular hydroamination of alkynes in. Phasetransfercatalyzed intramolecular hydroaryloxylation. A study on the gold icatalyzed intramolecular hydroamination of trichloroacetimidates derived from propargyl and homopropargyl alcohols is described. Jun 25, 2015 frustrated lewis pairs flps based on sterically encumbered anilines and the lewis acid bc 6 f 5 3 were found to react with terminal alkynes effecting intermolecular hydroamination affording iminium alkynylborate species of the form rphn cr.
Developing transitionmetal catalysts for the intramolecular hydroamination of alkynes. In the absence of a ligand, the selectivity of the reaction is dependent upon the nature of the counteranion and solvent. The introduction of nonchelating nitrogeneous ligands suppresses competitive bronsted acid catalys. The catalytic synthesis of linear secondary amines using the schafer titanium catalyst was accomplished through an intermolecular hydroamination of terminal alkynes followed by a pdc hydrogenation. Intramolecular copetype hydroamination of alkenes and. Intramolecular metalcatalyzed hydroamination of alkynes, leading to. Catalyzed intramolecular asymmetric hydroamination, hydroalkoxylation, and hydrocarbonation of alkynes. Mechanism of the intramolecular hydroamination of alkenes. Intramolecular hydroamination of unactivated alkenes nitrogencontaining heterocycles are to be found in a large number of natural products of interest. Intramolecular hydroamination of alkynes catalyzed by. Use of group 4 bissulfonamido complexes in the intramolecular hydroamination of alkynes and allenes lutz ackermann, robert g. Catalytic asymmetric intramolecular hydroamination of alkynes in the presence of a catalyst system consisting of pd0methyl norphos or tolyl renorphosbenzoic acid. Metalcatalyzed enantioselective intramolecular hydroamination of olefins 1 is one of the most conceptually simple and atomeconomical approaches to the construction of enantioenriched nitrogen heterocycles, 2 which are valuable synthons in the preparation of natural products and biologically active molecules. Request pdf isoindoles and dihydroisoquinolines by goldcatalyzed intramolecular hydroamination of alkynes.
Pvp, catalyzed the intramolecular hydroamination of toluenesulfonamides to unactivated alkenesalkynes in etoh under aerobic and basic conditions. Intramolecular hydroamination has been successfully applied in the synthesis of biologically relevant compounds, but intermolecular hydroamination is less commonly employed in synthesis, due to the possible formation of multiple regioisomers. Catalyzed intramolecular hydroamination of alkynes. For the intermolecular alkynes hydroamination synthesis of the. Consecutive intramolecular hydroaminationasymmetric transfer. Catalytic hydroaminations of alkenes, allenes, and dienes which may be inter or intramolecular afford amines, imines, and enamines eq. Goldi catalysed regio and stereoselective intermolecular. Hydrogenation and hydroamination reactions using boronbased.
Intra and intermolecular hydroamination of alkynes catalyzed by. The first rhodiumcatalyzed asymmetric intramolecular hydroamination of unactivated olefins was developed by using dialkylbiaryl phosphine ligands see scheme. Rhodiumcatalyzed asymmetric intramolecular hydroamination. In these cases, the reagent ratio of borane, aniline, and alkyne is 1. The catalyst can be used at relatively low loadings and without the need for added ligands or other cocatalysts. Rareearth metal complexes are highly efficient catalysts for intramolecular hydroamination of various cc unsat urations such as alkenes, alkynes, allenes. Silvercatalysed intramolecular hydroamination of alkynes with trichloroacetimidates valerie h. Mungra, jin zhu department of polymer science and engineering, school of chemistry and chemical engineering, state key laboratory of coordination chemistry, nanjing national laboratory of microstructures, nanjing university, nanjing 210093, p. Directed organocatalytic intermolecular copetype hydroamination of alkenes by peter joseph ng thesis submitted to the faculty of graduate and postdoctoral studies university of ottawa in partial fulfillment of the requirements for the m. Sunoj the journal of organic chemistry 2018 83 5, 26272639. The title compounds are enantioselectively synthesized in just two preparative steps. Hydroamination is the addition of an nh bond of an amine across a carboncarbon multiple bond of an alkene, alkyne, diene, or allene.
Intramolecular alkyne hydroalkoxylation and hydroamination. Request pdf palladiumcatalyzed intramolecular asymmetric hydroamination, hydroalkoxylation, and hydrocarbonation of alkynes a. In recent years hydroamination has received an increasing amount of attention as a direct and atomefficient method to access nitrogencontaining compounds. The use of agntf 2 as catalyst enables a facile, economic, regioselective, and highyielding protocol for the hydroamination of unsymmetrical internal alkynes under mild reaction conditions. Hydroamination reactions of alkenes organic reactions wiki. The reaction condi tions and the scope of the process are examined. Highly regioselective agntf 2catalyzed intermolecular hydroamination of alkynes with anilines xu zhang, bin yang, guangzhao li, xin shu, divyesh c.
The clean formation of products allowed for a facile synthesis and isolation of 23 examples of secondary amines in yields of 3399%. Dimethylaminoacrylate derivatives were also obtained with high yields. Chapter 2a basemediated hydroamination of symmetrical. Intramolecular hydroamination of alkynes catalyzed by silver. Intramolecular hydroamination of unactivated alkenes. Amines are invaluable precursors and necessary chemical components in industrial settings as well as pharmaceutical industries, making methods for efficient formation of cn bonds a vital chemical process. Goldi catalysed regio and stereoselective intermolecular hydroamination of internal alkynes was developed for the effective synthesis of a series of zfunctionalised vinylazoles under solvent free conditions. C bonds is an atom economical strategy to construct n.
Intramolecular hydroamination of alkynes catalyzed by pdpph34. Rhodiumcatalyzed asymmetric intramolecular hydroamination of. Silvercatalysed intramolecular hydroamination of alkynes with trichloroacetimidates. Rhodium catalyzed asymmetric hydroamination of internal alkynes with indoline. The journal of organic chemistry 2008, 73 24, 96989709.
An efficient, atomeconomic and green approach to synthesizing enamines was developed by intermolecular hydroamination of activated alkynes with high yields under catalyst and solventfree conditions. The protocol, with a semihollowshaped triethynylphosphine as a ligand for gold, allowed the synthesis of a variety of azepine derivatives, which are difficult to access by other methods. The goldcatalyzed, sevenmembered ring forming, intramolecular hydroamination of alkynic sulfonamides has been investigated. Dean toste department of chemistry, university of california, berkeley, california 94720 received december 9, 2006. Catalytic activity of gold nanoclusters in intramolecular. The familiar intramolecular alkyne hydroamination was reported by crabtrees group to be catalyzed by an iridium hydride catalyst 1. This chapter deals with hydroamination reactions catalyzed by s. Coupled with the limitations of traditional cn bond formation reactions, there is much interest in catalytic hydroamination as a route to nitrogen heterocycles. The intramolecular hydroamination reaction is among the more versatile means of forming nitrogencontaining hetereocycles, compounds of interest in a variety of chemical disciplines. A variety of 2methylpyrrolidines have been synthesized with high enantioselectivities. The ratedetermining step in the catalytic cycle for alkyne hydroamination with lanthanide catalysts is binsertion, as it was for alkenes. This strategy is efficient to build complex structures from simple starting materials in an environmentally compatible fashion.
In this paper, we describe the intramolecular hydroamination of tolenesulfonamides to substrates with carboncarbon multiple bonds including unactivated alkenes and alkynes, along with some additional results to provide insight into the reaction mechanism. Phasetransfercatalyzed intramolecular cyclization reaction of forming benzobfuran and 3methyleneisoin doline1one derivatives has been developed. Organometallic catalysts for intramolecular hydroamination of. In this context, we expected that the use of l1 as a ligand in the goldcatalyzed intramolecular hydroamination of alkynes would enable the construction of nitrogencontaining heterocyclic sevenmembered rings, and we applied the triethynylphosphinegoldi catalytic systems to the synthesis of azepine derivatives through intramolecular. However, older results and intramolecular reactions will be. Intramolecular hydroamination of alkenes early main. However, if it is necessary for the discussion, older results and intramolecular reactions, which can be achieved more easily, will be mentioned as well. Reductive deoxygenation occurs in the particular case of aryl ketones. The reaction proceeds via antiaddition of toluenesulfonamide to the alkenes assisted by.
Amines are common in finechemical, pharmaceutical, and agricultural industries. While the reaction has been intensely studied, concerns still exist over its amenability to organic synthesis. Gold i catalyzed enantioselective intramolecular hydroamination of allenes rebecca l. Intramolecular hydroamination of alkynic sulfonamides. Palladiumcatalyzed intramolecular asymmetric hydroamination of alkynes article in journal of the american chemical society 1266. Highly regioselective agntf 2 catalyzed intermolecular. Intramolecular hydroalkoxylation and hydroamination of. Nitrogencontaining molecules are ubiquitous in both natural products and pharmaceutical drugs, thus an efficient method for. In the ideal case, hydroamination is atom economical and green.
The direct addition of a nh bond across a carboncarbon multiple bond, the hydroamination reaction, constitutes an atomeconomical method for the synthesis of substituted amines. Organometallic catalysts for intramolecular hydroamination. Palladiumcatalyzed intramolecular asymmetric hydroamination, hydroalkoxylation, and hydrocarbonation of alkynes. Sequential intermolecular hydroamination of alkynes and. Basemediated hydroamination of symmetrical internal alkynes 25 scheme 2a. Similar alkyne hydroaminations using iridium catalysis were. Nitrogencontaining molecules are ubiquitous in both natural products and pharmaceutical drugs, thus an efficient method for the formation of these motifs is of great importance.
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