182. Macrocyclic acetylenic compounds. Part I. Cyclotetradeca-1 :3-diyne and related compounds

Eglinton, G.; Galbraith, A. R.

doi:10.1039/jr9590000889

Cited by 294 publications

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“…SRAAC and SRACA to Diynes We first investigated the radical cyclization of the readily available diynes 6a-d 7,8) (Chart 2, Table 1). A solution containing thiophenol (1 eq) and 2,2Ј-azobisisobutyronitrile (AIBN) (0.5 eq) in benzene was added dropwise to a solution of an unbranched diyne, 1,6-heptadiyne (6a) in boiling benzene while stirring under nitrogen.…”

Section: Resultsmentioning

confidence: 99%

“…The organic phase was washed with H 2 O, dried over MgSO 4 , and concentrated under reduced pressure. Purification of the residue by medium-pressure column chromatography (hexane) afforded 13c (25.5 mg, 14%), 14c (46.6 mg, 25%), and 15c (31.5 mg, 17% 3.11 (1H,dd,Jϭ13,6.5 Hz),3.12 (1H,ddd,Jϭ12,7.5,4 Hz),3.33 (1H,ddd,Jϭ12,8,3.5 Hz),3.74 (1H,d,Jϭ13.5 Hz),3.97 (1H,d,Jϭ13.5 Hz), 6.13 (1H, br s), m),7.69 (2H,d,Jϭ8 Hz). NOE was observed between methylene-H (d 2.88, 3.11) and olefinic-H (d 6.13) 3.40 (6/5H,br t,Jϭ7 Hz),4.15 (4/5H,d,Jϭ2.5 Hz),4.22 (6/5H,d,Jϭ2.5 Hz),m),6.26 (2/5H,dt,Jϭ14.5,1 Hz),6.32 (3/5H,dt,Jϭ9,1 Hz), …”

Section: Sulfanyl Radical Reaction Of Adduct 10amentioning

confidence: 99%

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Radical Cyclization in Heterocycle Synthesis. 12. Sulfanyl Radical Addition-Addition-Cyclization (SRAAC) of Unbranched Diynes and Its Application to the Synthesis of A-Ring Fragment of 1.ALPHA.,25-Dihydroxyvitamin D3.

Miyata

Nakajima

Naito

2001

CHEMICAL & PHARMACEUTICAL BULLETIN

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Radical cyclization is a useful method for the preparation of various cyclic compounds.1) Recently, this method in which carbon centered radical species are generated by the addition reaction of a radical to a multiple bond has drawn the attention of synthetic chemists because of its several advantages, such as readily available starting substrate and formation of functionalized products. The synthetic utility of this type of approach using diene and enyne systems has been partially shown.2,3) To our knowledge, there have been only a few papers published on the radical cyclization of diynes, 4) which requires drastic conditions for successful radical cyclization. Furthermore, diynes 1 (XϭC(COOMe) 2 ) having a quaternary carbon have been employed as substrates, because the cyclization reaction is facilitated by the Thorpe-Ingold effect and reactive rotamer effect.5) Unbranched diyne 1 (XϭCH 2 ) has been reported to yield no cyclized product but only an acyclic adduct. 4a,6) We found that the sulfanyl radical-induced cyclization of unbranched diyne 1 (XϭCH 2 ) proceeded smoothly by employing 2 eq of thiophenol under mild conditions to give cyclized product 2 as the major product in moderate yield (Chart 1). Additionally, we disclosed that the feasibility of the sulfanyl radical addition and/or cyclization is dependent upon the structure of the substrates. In the case of unbranched 1,6-heptadiyne 1 (nϭ1, XϭCH 2 ), sulfanyl radical addition-addition-cyclization (SRAAC) proceeded smoothly to give cyclized product 2 having an exo-olefin as the major product, while in the case of 1,6-heptadiyne 1 (nϭ1, XϭC(COOMe) 2 , NTs) having either a quaternary carbon or a heteroatom, sulfanyl radical addition-cyclization-addition (SRACA) occurred to give endoolefin 3. In the case of longer carbon chain, 1 (nϭ2, XϭCH 2 , C(COOMe) 2 ) gave exo-olefin 2 as the major product, while 1 (nϭ2, XϭNSO 2 Ar) gave a complex mixture. Synthetic utility of newly found SRAAC has been proved by a novel synthesis of A-ring fragment 5 of 1a,25-dihydroxyvitamin D 3 (1a,25-(OH) 2 D 3 ). Results and DiscussionSRAAC and SRACA to Diynes We first investigated the radical cyclization of the readily available diynes 6a-d 7,8) (Chart 2, Table 1). A solution containing thiophenol (1 eq) and 2,2Ј-azobisisobutyronitrile (AIBN) (0.5 eq) in benzene was added dropwise to a solution of an unbranched diyne, 1,6-heptadiyne (6a) in boiling benzene while stirring under nitrogen. The solution was then refluxed for a further 2 h and separation of the crude product gave the cyclic products 7a (E : Zϭ 10 : 1) and 8a in 21 and 19% yields, respectively, along with the recovered volatile starting material 6a and acyclic adduct 10a as a mixture of (E )-and (Z )-isomers (entry 1). 10a was also obtained but in 17% yield by radical reaction of 6a using 2,2Ј-azobis(2,4-dimethyl-4-methoxyvaleronitrile) (V-70) 9) as radical initiator at room temperature. When 2 eq of thiophenol was used in the presence of AIBN, the reaction proceeded smoothly to give the exo-olefin 7a (E : Zϭ8 : 1)...

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Section: Resultsmentioning

confidence: 99%

Section: Sulfanyl Radical Reaction Of Adduct 10amentioning

confidence: 99%

Radical Cyclization in Heterocycle Synthesis. 12. Sulfanyl Radical Addition-Addition-Cyclization (SRAAC) of Unbranched Diynes and Its Application to the Synthesis of A-Ring Fragment of 1.ALPHA.,25-Dihydroxyvitamin D3.

Miyata

Nakajima

Naito

2001

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…The reaction system employed by White was 0.150 g (0.0015 mol) Cu(l)Cl, 0.23 mL (0.0015 mol) TMEDA, 1.7 mL pyridine in 48 mL 1,2-dichlorobenzene; to this was added 0.0396 mol a,w-alkyldiyne in 10 mL 1,2-dichlorobenzene (a 1: 1 molar ratio of Cu(1)CI:TMEDA was used). Also, since high monomer concentrations were employed it would seem less likely that the a,w-alkyldiynes would cyclize on polymerization (7).…”

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confidence: 99%

Synthesis and characterization of a series of poly(α,ω-alkyldiynes) and copoly(α,ω-alkyldiynes)

Kennedy¹,

MacCallum²,

MacKerron³

1995

Can. J. Chem.

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A series of poly(a,o-alkyldiynes) and copoly(a,w-alkyldiynes) were synthesized by catalytic Glaser coupling reactions. Two routes were investigated and developed. These routes were chosen in anticipation that high molar mass, linear and polydisperse, polymers would be achieved. GPC (gel permeation chromatography) curves revealed that this was possible for the majority of polymers synthesized by the first route. However, a wide range of molar masses were obtained by the second route with a significant low molar mass tail present in almost all GPC curves. Very low M, (number average molar mass) values by GPC gave correspondingly very high M, values by end-group analysis (EGA). Hence, it was proposed that the low molar mass tail was a consequence of cyclic structures. From these results and observations a mechanism for the polymerization of the a,o-alkyldiynes was proposed.Key words: poly(a,o-alkyldiynes), Glaser coupling, molar mass.Resume : On a synthCtisC une sCrie de poly(a,w-alkyldiynes) et de copoly(a,o-alkyldiynes) par les rkactions de couplage catalytique de Glaser. On a CtudiC et dCveloppC deux voies. Ces voies ont Ct C choisies dans le but d'obtenir des polymkres lintaires et polydispersks de poids molCculaires ClevCs. Des courbes de chromatographie par permtation de gel (GPC) ont rCvklk que ceci est possible pour la majoritt des polymkres synthCtisCs par la premikre voie. Toutefois, la seconde voie a conduit 21 de grandes variations dans les poids molCculaires et, dans chaque cas, les courbes de GPC ont toutes prCsentCes des trainCes avec des quantitCs importantes de produits de faibles poids molCculaires. Des valeurs trks faibles de M,, (valeur moyenne de la masse molaire) par GPC fournissent des valeurs correspondantes ClevCes de M,, par l'analyse des groupes terminaux (EGA). On suggkre donc que les trainees de faible poids molCculaire sont une constquence de structures cycliques. Sur la base de ces rksultats et de I'ensemble des observations, on propose un mtcanisme pour la polymtrisation des a,o-alkyldiynes.

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“…These approaches include Glaser's coupling, 15 Eglinton's coupling, 16 and Hay's coupling. 17 In these reactions, the transmetalation of an alkynyl group to copper is proposed to generate an alkynylcopper species that undergoes subsequent oxidative dimerization to give the corresponding 1,3-butadiynes.…”

Section: Introductionmentioning

confidence: 99%

“…11 These conjugated diynes also serve as the core functional group in organic molecular materials such as linearly σ-conjugated acetylenic oligomers and polymers, 12 macrocycles 13 (Figure 1), and supramolecular scaffolds. 14 Oxidative dimerization of sp-hybridized terminal alkynes mediated by Cu(I) or Cu(II) salts under either catalytic or stoichiometric conditions is the most commonly used synthetic methodology for obtaining symmetrically substituted 1,3-butadiyne.These approaches include Glaser's coupling, 15 Eglinton's coupling, 16 and Hay's coupling. 17 In these reactions, the transmetalation of an alkynyl group to copper is proposed to generate an alkynylcopper species that undergoes subsequent oxidative dimerization to give the corresponding 1,3-butadiynes.…”

mentioning

confidence: 99%

Synthesis of 1,3-diynes via detelluration of bis(ethynyl)tellurides

Stefani

Pena

Zukerman-Schpector

et al. 2011

J. Braz. Chem. Soc.

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Neste artigo é descrita a síntese de sistemas diínicos conjugados contendo substituintes elétron-atratores e elétron-doadores via a deteluração catalizada por paládio de bis-(ariletinil)teluretos e bis-(alquiletinil)teluretos. Este procedimento foi realizado sob condições atmosféricas em DMF usando Pd(Oac) 2 como catalisador e AgOAc como um aditivo na presença de trietilamina. Esta rota oferece acesso eficiente a sistemas diínicos conjugados em um curto período de tempo. A estrutura cristalográfica por difração de raios X do telureto de bis(p-toluiletinila) e a conformação no estado sólido mostram uma cadeia supramolecular alinhada ao longo do eixo b, sustentada por interações CH…p.The synthesis of symmetric conjugated diyne systems with electron-withdrawing or electrondonating substituents via a palladium-catalyzed detelluration of bis(arylethynyl)tellurides and bis(alkylethynyl)tellurides is described. This procedure is effected under atmospheric conditions in DMF using Pd(OAc) 2 as a catalyst and AgOAc as an additive in the presence of triethylamine. This route offers efficient access to conjugated diyne systems in short reaction time. X-ray crystallographic structure and solid-state conformation of bis(p-tolylethynyl)telluride show a supramolecular chain aligned along the b axis, sustained by C-H…p interactions.Keywords: tellurium, bis(phenylethynyl)tellurides, bis(alkynylethynyl)tellurides, detelluration, diynes, palladium IntroductionOrganotellurium compounds play an important role in organic synthesis, and they have received considerable attention because of their potential availability and useful biological activity. 1 As reported by Bergman and co-workers 2 more than three decades ago, aryltelluriums undergo detelluration upon treatment with degassed Raney nickel to afford biaryl compounds. Although the reaction is interesting and synthetically useful, the necessity of more than a stoichiometric amount of the required metal is still a serious drawback. However, attempted transition metalcatalyzed detellurations have been unsuccessful to date. 2,3 Compounds containing chains of conjugated triple bonds 4,5 are of paramount importance as versatile and useful building blocks in organic synthesis. Among these compounds, 1,3-butadiynes 6 have been prominently utilized as substructures in the formation of valuable intermediates for natural products 7 and pharmaceuticals such as antitumor, 8 antibacterial, 9 anti-inflammatory, 10 and antifungal agents. 11 These conjugated diynes also serve as the core functional group in organic molecular materials such as linearly σ-conjugated acetylenic oligomers and polymers, 12 macrocycles 13 (Figure 1), and supramolecular scaffolds. 14 Oxidative dimerization of sp-hybridized terminal alkynes mediated by Cu(I) or Cu(II) salts under either catalytic or stoichiometric conditions is the most commonly used synthetic methodology for obtaining symmetrically substituted 1,3-butadiyne.These approaches include Glaser's coupling, 15 Eglinton's coupling, 16 and Hay's coupling. 17 In t...

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182. Macrocyclic acetylenic compounds. Part I. Cyclotetradeca-1 :3-diyne and related compounds

Cited by 294 publications

References 0 publications

Radical Cyclization in Heterocycle Synthesis. 12. Sulfanyl Radical Addition-Addition-Cyclization (SRAAC) of Unbranched Diynes and Its Application to the Synthesis of A-Ring Fragment of 1.ALPHA.,25-Dihydroxyvitamin D3.

Radical Cyclization in Heterocycle Synthesis. 12. Sulfanyl Radical Addition-Addition-Cyclization (SRAAC) of Unbranched Diynes and Its Application to the Synthesis of A-Ring Fragment of 1.ALPHA.,25-Dihydroxyvitamin D3.

Synthesis and characterization of a series of poly(α,ω-alkyldiynes) and copoly(α,ω-alkyldiynes)

Synthesis of 1,3-diynes via detelluration of bis(ethynyl)tellurides

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