Substituent effects on the cyclization mode of 7-sulfonyl-3-hepten-1,5-diynes and 11-sulfonylundeca-3,7-dien-1,5,9-triynes

Wu, Huey-Juan; Lin, Chi‐Wen; Lee, Jeng‐Lin; Lu, Wan Chen; Lee, Chia‐Ying; Chen, Chin‐Chau; Wu, Ming‐Jung

doi:10.1016/j.tet.2004.02.067

Cited by 16 publications

(12 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2′‐Formyl‐4‐methoxy‐1,1′‐biphenyl (14): 1 H NMR (200 MHz, CDCl 3 ): δ = 3.86 (s, 3 H), 7.00 (d, J = 8.8 Hz, 2 H), 7.30 (d, J = 8.8 Hz, 2 H), 7.47 (m, 2 H), 7.61 (td, J = 1.6 and 7.3 Hz, 1 H), 8.01 (m, 1 H), 10.00 (s, 1 H) ppm. Data in accordance with previously reported results 17…”

Section: Methodssupporting

confidence: 93%

N‐Heterocyclic Benzhydrylamines as New N,N‐Bidentate Ligands in Palladium Complexes: Synthesis, Characterization and Catalytic Activity

2008

View full text Add to dashboard Cite

The synthesis of new N,N‐bidentate ligands based on a π‐deficient N‐heterocyclic benzhydrylamine core is described. The corresponding air‐stable palladium complexes are obtained in high yields and fully characterized by NMR spectroscopy and X‐ray structure determination. These new phosphane‐free catalytic systems proved efficient in the Suzuki–Miyaura reaction, enabling us to obtain biaryl products in good yields, also for reactions with o‐substituted phenyl chlorides as starting materials. The effects of both electronic and steric modulations at the benzhydrylamine core on the catalytic activity are also described.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

show abstract

Section: Methodssupporting

confidence: 93%

N‐Heterocyclic Benzhydrylamines as New N,N‐Bidentate Ligands in Palladium Complexes: Synthesis, Characterization and Catalytic Activity

2008

View full text Add to dashboard Cite

show abstract

“…However, radical and anionic endo cyclizations are stereoelectronically handicapped and, despite the help of aromaticity, the 6-endo-dig cyclizations are often slower than their 5-exo-dig counterparts . Consequently, the radical endo cascades of oligoalkynes are nonselective. − …”

Section: Routes To Endo-dig Products and Cyclization Cascadesmentioning

confidence: 99%

Alkyne Origami: Folding Oligoalkynes into Polyaromatics

Alabugin

González-Rodríguez

2018

Acc. Chem. Res.

View full text Add to dashboard Cite

Do not bend the triple bonds! This familiar undergraduate mantra must be disobeyed if the alkyne group is used as a building block in molecular construction. This Account will describe our exploits in "alkyne origami", that is, folding oligoalkynes into new shapes via cyclization cascades. This research stems from a set of guidelines for the cyclizations of alkynes that we suggested in 2011 ( Gilmore Chem. Rev. 2011 , 111 , 6513 ; Alabugin J. Am. Chem. Soc. 2011 , 133 , 12608 ). The guidelines blended critical analysis of ∼40 years of experimental research with computations into the comprehensive predictions of the relative favorability of dig-cyclizations of anions and radicals. In this Account, we will show how this new understanding has been instrumental in building polyaromatics. In particular, we illustrate the utility of these stereoelectronic models by developing a toolbox of practical, selective, and efficient synthetic transformations. The high energy and high carbon content render alkynes the perfect precursors for the preparation of polyaromatic ribbons and other carbon-rich materials with precisely controlled structure and reactivity. Still, the paradox of alkyne reactivity (alkynes store a lot of energy but are protected kinetically by their relatively strong π-bonds) requires precise use of stereoelectronic factors for lowering the activation barriers for alkyne cyclizations. These factors are drastically different in the "all-exo" and the "all-endo" cyclization cascades of oligoynes. This Account will highlight the interplay between the stereoelectronics of bond formation and topology of acyclic precursor "folding" into a polycyclic ribbon. The topology of folding is simpler for the endo cascades, which are compatible with initiation either at the edge or at the center. In contrast, the exo cascades require precise folding of an oligoalkyne ribbon by starting the cascade exactly at the center of the chain. These differences define the key challenges in the design of these two types of alkyne cyclization cascades. For the endo processes, the folding is simple, but these processes require a strategy ("LUMO Umpolung") for inverting the usual stereoelectronic requirements of alkyne cyclizations. We also show how alkenes can be used as alkyne equivalents in cyclizations coupled with fragmentations and how one can make endo cyclization products without ever going through an endo cyclization. In contrast, each elementary step of the exo cascades benefits from the inherent exo preference for the radical attack, but these cascades require precise initiation by starting exactly at the central alkyne unit of the oligoyne. This strict selectivity requirement led to the development of traceless directing groups capable of supramolecular assistance to the initiation step and self-terminating departure at the end of the cascade. With attention to electronic effects that can stop radical cascades, oligoalkynes can be selectively converted into precisely shaped and functionalized polyaromatic products. The generali...

show abstract

“…2′-Formyl-[1,1′-biphenyl]-2-carbonitrile (1a). 21 The crude was purified by flash chromatography on silica gel (petroleum ether/ EtOAc, 5:1) to give the product 1a in 74% yield (307 mg) as a white solid. mp 70.5−72.4 °C; 1 H NMR (400 MHz, CDCl 3 ) δ 9.88 (d, J = 0.6 Hz, 1H), 8.07 (dd, J = 7.7, 1.5 Hz, 1H), 7.81 (dd, J = 7.8, 1.3 Hz, 1H), 7.71 (td, J = 7.6, 1.2 Hz, 1H), 7.68 (td, J = 7.6, 1.6 Hz, 1H), 7.63 (t, J = 7.6 Hz, 1H), 7.55 (td, J = 7.7, 1.3 Hz, 1H), 7.44 (dd, J = 7.6, 0.8 Hz, 1H), 7.43 (dd, J = 7.7, 1.5 Hz, 1H); 13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ 190.9, 142.3, 141.0, 134.0, 134.0, 133.2, 132.6, 131.3, 131.2, 129.5, 129.5, 128.7, 117.8, 113.2; IR (KBr): 2222, 1587, 1251, 1094, 881, 792 cm −1 .…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…10-Phenylphenanthren-9-amine (4b). 21 The crude was purified by flash chromatography on basic Al 2 O 3 (petroleum ether/EtOAc, 20:1) to give the product 4b in 81% yield (44 mg) as a white solid. mp 115.2−116.3 °C; 1 H NMR (400 MHz, DMSO-d 6 ) δ 8.84 (d,J = 8.0 Hz,1H),1H),8.28 (dd,J = 7.8,1.7 Hz,1H),2H),2H),1H),4H),1H), 4.98 (s, 2H); 13 C{ 1 H} NMR (100 MHz, DMSO-d 6 ) δ 143.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Cascade Reaction of Arylboronic Acids and 2′-Cyano-biaryl-2-aldehyde N-Tosylhydrazones: Access to Functionalized 9-Amino-10-arylphenanthrenes

et al. 2018

View full text Add to dashboard Cite

An efficient, general, and convenient protocol for the synthesis of functionalized 9-amino-10-arylphenanthrene derivatives using a catalystfree cascade reaction of arylboronic acids and 2′-cyano-biaryl-2-aldehyde Ntosylhydrazones is described. The synthesis was carried out via simple experimental conditions using Na 2 CO 3 in 1,4-dioxane as a solvent. Moreover, the 9-amino-10-arylphenanthrene compounds were also obtained on a gram scale and further derivatized to synthesize the fused phenanthrene derivatives.

show abstract

Substituent effects on the cyclization mode of 7-sulfonyl-3-hepten-1,5-diynes and 11-sulfonylundeca-3,7-dien-1,5,9-triynes

Cited by 16 publications

References 10 publications

N‐Heterocyclic Benzhydrylamines as New N,N‐Bidentate Ligands in Palladium Complexes: Synthesis, Characterization and Catalytic Activity

N‐Heterocyclic Benzhydrylamines as New N,N‐Bidentate Ligands in Palladium Complexes: Synthesis, Characterization and Catalytic Activity

Alkyne Origami: Folding Oligoalkynes into Polyaromatics

Cascade Reaction of Arylboronic Acids and 2′-Cyano-biaryl-2-aldehyde N-Tosylhydrazones: Access to Functionalized 9-Amino-10-arylphenanthrenes

Contact Info

Product

Resources

About