Metal-free halogenation of arylboronate with N-halosuccinimide was written by Kamei, Toshiyuki;Ishibashi, Aoi;Shimada, Toyoshi. And the article was included in Tetrahedron Letters in 2014.Reference of 365564-07-4 This article mentions the following:
Efficient bromination and chlorination of aryl pinacol boronates were accomplished without the addition of metal reagent. The reaction proceeded efficiently with electron-rich arylboronates or heteroarylboronates in DMF or acetonitrile, to afford mono-, di-, or trihalogenated aryl pinacol boronates. In the experiment, the researchers used many compounds, for example, 2-(3,5-Dimethoxyphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (cas: 365564-07-4Reference of 365564-07-4).
2-(3,5-Dimethoxyphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (cas: 365564-07-4) belongs to ethers. Ether is less polar than esters, alcohols or amines because of the oxygen atom that is unable to participate in hydrogen bonding due to the presence of bulky alkyl groups on both sides of the oxygen atom. But ether is more polar than alkenes. Electron-deficient reagents are also stabilized by ethers. For example, borane (BH3) is a useful reagent for making alcohols. Pure borane exists as its dimer, diborane (B2H6), a toxic gas that is inconvenient and hazardous to use. Borane forms stable complexes with ethers, however, and it is often supplied and used as its liquid complex with tetrahydrofuran (THF).Reference of 365564-07-4
Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem