Introduction

2-Vinylnaphthalene (Figure 1) is an intermediate for synthesizing vinylnaphthalene polymers. Due to its active vinyl group, vinylnaphthalene finds widespread application as a pharmaceutical intermediate, dye intermediate, and raw material for optical element coatings. 2-Vinylnaphthalene imparts various characteristics to various polymer materials, such as high heat resistance, low dielectric constant, low dielectric loss, high refractive index, flame retardancy, and low moisture absorption.Herein,some application research will be introduced.

Vinylnaphthalene Polymerization

Vinylnaphthalenes can be regarded as one kind of styrene derivatives bearing aromatic-fused ring. Poly(vinylnaphthalenes) have become of interest owing to their potential applications as fluorescence tags and electron beam lithography resists as well as their interesting photophysical characteristics. However, the well controlled polymerization of vinylnaphthalene derivatives remains challenging since the uneven electron density distribution makes naphthalene highly susceptible to nucleophilic reagents and Friedel-Crafts reaction.Therefore, the polymerization of vinylnaphthalene monomers encounters great difficulty via cationic, anionic, and radical mechanisms. To date, few transition metal-based catalysts are reported to initiate the coordination polymerization of vinylnaphthalene albeit without stereospecific selectivity.

Coordination polymerizations of 1-vinylnaphthalene (1VN), 2-vinylnaphthalene (2VN) and 6-methoxy-2-vinylnaphthalene (MVN) are carried out at room temperature by using the half-sandwich scandium precursor FluSiMe3Sc(CH2SiMe3)2(THF) (1) and the constrained geometry configuration rare-earth metal precursors FluCH2PyLn(CH2SiMe3)2(THF)n [Flu= C13H8,Py=C5H4N; Ln=Sc(2a), n=0; Ln=Lu(2b), Y(2c), n=1]. Atactic poly(1VN) and perfect syndiotactic poly(2VN) and poly(MVN) are produced by precursors 2a-2c in a controlled way. Treatment of poly(MVN) with boron tribromide at ?20°C provides a syndiotactic poly(6-hydroxy-2-vinylnaphthalene).[1]

2-Vinylnaphthalene derivatives example

Monosubstituted derivatives of γ-cyclodextrin (γ-CD) are suitable building blocks for supramolecular polymers, and can also serve as precursors for the synthesis of other regioselectively monosubstituted γ-CD derivatives. They prepared a set of monosubstituted 2^I-O-, 3^I-O-,and 6^I-O-(3-(naphthalen-2-yl) prop-2-en-1-yl) derivatives of γ-CD using two different methods. Researchers present two approaches for the synthesis of naphthylallyl (NA) derivatives. The first approach is a cross-metathesis of peracetylated allyl derivatives of γ-CD with 2-vinylnaphthalene.The main advantage of this procedure is that a pure regioisomer of the product is obtained due to the regio-purity of the starting material. Unfortunately, this reaction is quite low yielding, and the isolation of the products is hard to perform.Moreover, the starting compound for this reaction has to be prepared from γ-CD in two steps involving complicated chromatographic separations. Thus, the overall yields of the pure NA regioisomers were only 2–5%. Therefore, they turned our focus to developing another method for the preparation of naphthylallyl derivatives, which is based on a direct alkylation of γ-CD with 2-(3-chloroprop-1-enyl)naphthalene.A key step of the first synthetic procedure is a cross-metathesis between previously described regioisomers of mono-O-allyl derivatives of γ-CD and 2-vinylnaphthalene which gives yields of about 16-25% (2-5% starting from γ-CD). To increase the overall yields, they have developed another method, based on a direct alkylation of γ-CD with 3-(naphthalen-2-yl)allyl chloride as the alkylating reagent.Highly regioselective reaction conditions, which differ for each regioisomer in a used base, gave the monosubstituted isomers in yields between 12-19%. Supramolecular properties of these derivatives were studied by DLS, ITC, NMR, and Cryo-TEM.[2]

2-vinylnaphthalene in nanomaterial

The strong fluorescence 2-vinylnaphthalene and acrylic acid polymer nanoparticles have been prepared under ultrasonic radiation. Based on the fluorescence quenching of polymer by Hg(II), a method for the selective determination of Hg(II) was developed. The reaction conditions between Hg(II) and polymer were investigated in detail. The assay is very few interference stable fluorescence signals (at least 2 h), simple instrument (common spectrofluorometer) and simple step. Under optimal experimental conditions, a limit of detection of 0.01
g ml?1 was achieved. The calibration curve was linear over the concentration range 0.04–0.1
g ml?1 with a correlation coefficient of 0.9927. The proposed method has been applied to the selective quantification of Hg(II) in synthetic samples with the satisfactory results.[3]

2-vinylnaphthalene in catalyst

Recent years have witnessed marked progress in the efficient synthesis of various enantioenriched 1,2,3,4-tetrahydroquinoxalines. However, enantio- and diastereoselective access to trans-2,3-disubstituted 1,2,3,4-tetrahydroquinoxalines remains much less explored. Herein researchers report that a frustrated Lewis pair based catalyst generated via in situ hydroboration of 2-vinylnaphthalene with HB(C₆F₅)₂ allows for the one-pot tandem cyclization/hydrosilylation of 1,2-diaminobenzenes and 1,2-diketones with commercially available PhSiH3 to exclusively afford trans-2,3-disubstituted 1,2,3,4-tetrahydroquinoxalines in high yields with excellent diastereoselectivities (>20:1 dr). Furthermore, this reaction can be rendered asymmetric by using an enantioenriched borane-based catalyst derived from HB(C₆F₅)₂ and a binaphthyl-based chiral diene to give rise to enantioenriched trans-2,3-disubstituted 1,2,3,4-tetrahydroquinoxalines in high yields with almost complete diastereo- and enantiocontrol (>20:1 dr, up to>99% ee). A wide substrate scope, good tolerance of diverse functionality and up to 20-gram scale production are demonstrated. The enantio- and diastereocontrol areachieved by the judicious choice of borane catalyst and hydrosilane. The catalytic pathway and the origin of the excellent stereoselectivity are elucidated by mechanistic experiments and DFT calculations.[4] 

References

[1]Li S, Yan F, Zhang Z, Dou Y, Zhang W, Cui D. Syndioselective Polymerization of Vinylnaphthalene. Macromol Rapid Commun. 2019;40(12):e1900061. doi:10.1002/marc.201900061

[2]Bláhová M, Filippov SK, Ková?ik L, et al. Synthesis and supramolecular properties of regioisomers of mononaphthylallyl derivatives of γ-cyclodextrin. Beilstein J Org Chem. 2017;13:2509-2520. Published 2017 Nov 27. doi:10.3762/bjoc.13.248

[3]Wang L, Dong L, Bian GR, Xia TT. Preparation of a novel fluorescence nanoparticles and its application in the determination of Hg(II). Spectrochim Acta A Mol Biomol Spectrosc. 2005;62(1-3):313-316. doi:10.1016/j.saa.2004.12.045

[4]Luo Z, Li Z, Zhao H, et al. Borane-Catalyzed Tandem Cyclization/Hydrosilylation Towards Enantio- and Diastereoselective Construction of trans-2,3-Disubstituted-1,2,3,4-Tetrahydroquinoxalines. Angew Chem Int Ed Engl. 2023;62(32):e202305449. doi:10.1002/anie.202305449