Practical Synthesis of (<i>Z</i>)-Polyaromatic and Heteroaromatic Vinylacetylenes

Hayford, Anthony; Kaloko, Joseph Jr.; El-Kazaz, Salwa; Bass, Gwen; Harrison, C. E.; Corprew, Thomas

doi:10.1021/ol0508173

Cited by 20 publications

(14 citation statements)

References 22 publications

(17 reference statements)

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“…Remarkably, compound 1b, recently prepared by a different protocol, 22 was obtained with our direct procedure in higher yield and stereoselectivity.…”

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confidence: 84%

Direct Preparation of Z-1,3-Enyne Systems with a TMS-Propargylic Sulfone: Application of a One-Pot Julia Olefination

Bonini¹,

Chiummiento²,

Videtta³

2006

Synlett

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A benzothiazolyl TMS-propargylic sulfone was subjected to one-pot Julia olefinations with a variety of aliphatic and aromatic aldehydes. Predominant Z-selectivity up to 98:2 and good chemical yields were obtained in a facile route to the desired Z-1,3-enyne moieties.Vinylacetylenes are important and direct precursors of conjugated p-systems, including dienic, diacetylenic and aromatic compounds which are common features in natural products. 1 Frameworks like 1 (Scheme 1) are frequently used in multistep syntheses of polyunsaturated compounds, suitable for subsequent coupling reactions after silyl deprotection. For example, the Z-1,3-enyne system is used in the preparation of cyclooctatetraenophanes (2) 2 and of 3-alkoxymethylindolizines (3), 3 the latter are potential new calcium entry blockers, chemotherapeutics and cardiovascular agents. The same moiety 1 is the key intermediate in several total syntheses of natural bioactive compounds like the alkaloid quinolizidine 217A (4) 4 and the (-)-siphonodiol (5), 5 an antifungal and antibacterial polyacetylene.As part of our ongoing projects on natural product syntheses we are interested in the development of an efficient method for the construction of such Z-1,3-enyne system starting from an appropriate acetylenic compound, and in the subsequent stereocontrolled formation of the conjugated double bond. For highly regio-and stereoselective double-bond formation, compatible with multifunctionalized compounds, the most generally applicable methods involve the direct olefination of carbonyl compounds as in the Wittig, 6 Peterson, 7 Johnson, 8 classical Julia 9 and onepot Julia 10 reactions, or the more recently developed olefin metathesis 11 and transition-metal-catalyzed crosscoupling 12 reactions.Together with the seminal work on modified Julia olefination, 10c we have found only a recent report 13 on the preparation of such enyne systems via one-pot reaction of propargylic sulfones with a,b-unsaturated aldehydes, but no applications in total syntheses. Moreover, the reported propargylic sulfones are alkyl-substituted at the end of the acetylenic bond (n-Bu and Me, respectively).We have recently developed a simple and highly efficient procedure for the preparation of different propargylic sulfones starting from the corresponding propargylic alcohols. 14 We have chosen the TMS-propargylic sulfone for a general application of the one-pot Julia reaction. With both benzothiazoyl (BT) sulfones and phenyltetrazoyl (PT) sulfones in hand, we have attempted the olefination with benzaldehyde (Table 1), which was not used with propargylic sulfones in the previously reported olefinations. 10,13 In the first attempts, olefination of sulfone 6a was conducted at -55°C in THF using KHMDS, according to the premetallated 15 or Barbier procedure. 16 Reactions afforded the required enyne 7 in 50% and 80% yields, with Z/E ratios of 87:13 and 96:4, respectively (Table 1, entries 1 and 2).The same Z-selectivity was obtained in the olefination of sulfone 6a with benzaldehyde using DME as solv...

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“…Remarkably, compound 1b, recently prepared by a different protocol, 22 was obtained with our direct procedure in higher yield and stereoselectivity.…”

mentioning

confidence: 84%

Direct Preparation of Z-1,3-Enyne Systems with a TMS-Propargylic Sulfone: Application of a One-Pot Julia Olefination

Bonini¹,

Chiummiento²,

Videtta³

2006

Synlett

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“…Solution state UV–visible spectra were measured with a Shimadzu UV-3600 spectrophotometer, and fluorescence spectra were measured using a Edison RF-5301PC spectrofluoremeter. Starting materials 2i , 2j , 2k , 2z , and 2za were synthesized following literature protocols.…”

Section: Methodsmentioning

confidence: 99%

“…Prepared according to a procedure reported by Jianbo, Wang, and co-workers, the mixture of ( E : Z = 1:1); yellow liquid (yield: 337.9 mg, 63%); 1 H NMR (400 MHz, CDCl 3 ) δ 7.47–7.40 (m, 4H), 7.38–7.33 (m, 7H), 7.24 (dd, J = 5.1, 1.2 Hz, 1H), 7.13 (dd, J = 3.7, 1.2 Hz, 1H), 7.05 (dd, J = 5.1, 3.7 Hz, 1H), 6.93 (dd, J = 5.1, 3.7 Hz, 1H), 6.87 (s, 1H), 6.73 (dd, J = 3.6, 1.1 Hz, 1H), 6.49 (s, 1H); 13 C NMR (101 MHz, CDCl 3 ) δ 143.9, 141.4, 140.8, 140.4, 140.2, 138.6, 130.4, 129.4, 128.7, 128.5, 128.5, 128.4, 128.3, 128.1, 128.5, 127.5, 127.2, 126.6, 126.5, 125.6, 104.3; HRMS (ESI) m / z : calcd for C 12 H 10 BrS [M + H] + : 264.9681; found: 264.9685.…”

Section: Methodsmentioning

confidence: 99%

“…Prepared according to a procedure reported by Jianbo, Wang, and co-workers, the mixture of ( E : Z = 1:1); yellow liquid (yield: 338.2 mg, 60%); 1 H NMR (400 MHz, CDCl 3 ) δ 7.44 (dd, J = 5.1, 1.2 Hz, 1H), 7.36–7.29 (m, 4H), 7.25 (d, J = 1.2 Hz, 1H), 7.15–7.11 (m, 3H), 7.08–7.03 (m, 3H), 6.95 (dd, J = 5.1, 3.7 Hz, 1H), 6.87 (s, 1H), 6.74 (dd, J = 3.6, 1.1 Hz, 1H), 6.46 (s, 1H); 13 C NMR (101 MHz, CDCl 3 ) δ 162.9 (d, J = 248.1 Hz), 162.7 (d, J = 247.8 Hz), 143.8, 140.3, 139.9, 139.2, 137.5, 137.4 (d, J = 3.3 Hz), 134.4, 134.3 (d, J = 3.5 Hz), 131.4, 131.3, 130.5, 130.4, 127.6, 127.4, 126.6, 125.9, 115.5 (d, J = 21.6 Hz), 115.5 (d, J = 21.6 Hz), 104.6, 104.2; HRMS (ESI) m / z : calcd for C 12 H 9 BrFS [M + H] + : 282.9587; found: 282.9583.…”

Section: Methodsmentioning

confidence: 99%

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Palladium-Catalyzed Domino Reaction for Stereoselective Synthesis of Multisubstituted Olefins: Construction of Blue Luminogens

et al. 2018

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The first Pd-catalyzed multicomponent reaction of aryl iodides, alkenyl bromides, and strained alkenes has been developed, which allowed us to synthesize a variety of multisubsituted olefins in yields of 45-96% with excellent stereoselectivity. The configuration of the product was controlled by the configuration of the alkenyl bromides. Moreover, this practical methodology employing readily available substrates was found to be tolerant to a wide range of functional groups. Fifty six examples of highly stereoselective tri- or tetrasubstituted olefins have been successfully synthesized via this methodology. Most of the synthesized tetrasubstituted olefins are good aggregation-induced emission (AIE) luminogens.

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“…Although a variety of methods for their synthesis have emerged, there is still significant need for more direct methods to afford functionalized indolizine derivatives. During their work on the practical synthesis of ( Z )-heteroaromatic vinylacetylenes, Hayford et al serendipitously found the formation of indolizines upon desilylation of ( Z )-2-pyridine-silylated vinylacetylene with cesium or potassium fluoride and different alcohols as solvents or cosolvents (Figure ) . A mechanistic pathway involving a Michael-type addition to the vinylacetylene and subsequent six-electron electrocyclic ring closure to afford the indolizine was proposed (Figure ).…”

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confidence: 99%

Mechanistic Investigation on the Formation of Indolizines from 2-Enynylpyridines

et al. 2009

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Practical Synthesis of (Z)-Polyaromatic and Heteroaromatic Vinylacetylenes

Cited by 20 publications

References 22 publications

Direct Preparation of Z-1,3-Enyne Systems with a TMS-Propargylic Sulfone: Application of a One-Pot Julia Olefination

Direct Preparation of Z-1,3-Enyne Systems with a TMS-Propargylic Sulfone: Application of a One-Pot Julia Olefination

Palladium-Catalyzed Domino Reaction for Stereoselective Synthesis of Multisubstituted Olefins: Construction of Blue Luminogens

Mechanistic Investigation on the Formation of Indolizines from 2-Enynylpyridines

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