An Azide‐Substituted Triarylborane: A Key Compound for the Facile Synthesis of Fluorescent Triarylboranes Bearing Triazole Moieties as Connectable π‐Conjugated System Linkages

Abstract

Tris(4‐azido‐2,6‐dimethylphenyl)borane was readily synthesized from an amino‐substituted triarylborane using tert‐butyl nitrite and trimethylsilylazide. This compound can easily be converted into triarylboranes bearing various π‐conjugated moieties with triazole ring π‐linkers through a Huisgen cycloaddition. UV/Vis absorption spectra and DFT calculations suggested that constructing a triazole linker successfully extended the π‐conjugated system of triarylboranes. Triarylboranes obtained using this method maintained their fluorescent nature. In particular, the triarylborane linking N,N‐dimethylaminophenyl groups with triazole rings exhibited notable visible solvatofluorochromism and fluorescence color change upon addition of a fluoride anion.

o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

“…This strategy smartly avoided the N 1/ N 2 regioselective problem in conventional alkylation reaction of benzotriazoles. Beside the aforementioned examples, this transition-metal-free aryne-azide [3 + 2] cycloaddition protocol turned out to be quite general and has found a broad spectrum of synthetic applications. − …”

Synthesis of Highly Functionalizable Symmetrically and Unsymmetrically Substituted Triarylboranes from Bench‐Stable Boron Precursors

“…Overview of reported follow-up reactions, to which the BXyl 3 moiety (BAr 3 or BAr 2 Ar') is tolerant, and selected functional groups that have been attached. Examples of each path are given in the following references: a, [26][27][28][29][30] b, [27,[29][30][31][32][33] c, [34,35] d, [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] e, [52][53][54][55][56][57] f, [42,[58][59][60][61][62] g, [63][64][65][66][67] and h. [68][69][70][71]…”

“…For example, water solubility of triarylboranes can be facilitated by the introduction of cationic ammonium or phosphonium substituents (Figure 2e and f). [42,[52][53][54][55][56][57][58][59][60][61][62] Due to the limited synthetic access to unsymmetrically substituted triarylboranes, structure-property relationship studies have been mostly limited to symmetrically substituted triarylboranes (BAr 3 or BAr 2 Ar'). Consequently, even though a plethora of functional groups is available, a maximum of two can be realized at once.…”

“… Overview of reported follow‐up reactions, to which the BXyl 3 moiety (BAr 3 or BAr 2 Ar’) is tolerant, and selected functional groups that have been attached. Examples of each path are given in the following references: a,[ 26 , 27 , 28 , 29 , 30 ] b,[ 27 , 29 , 30 , 31 , 32 , 33 ] c,[ 34 , 35 ] d,[ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ] e,[ 52 , 53 , 54 , 55 , 56 , 57 ] f,[ 42 , 58 , 59 , 60 , 61 , 62 ] g,[ 63 , 64 , 65 , 66 , 67 ] and h.[ 68 , …”

“…For example, water solubility of triarylboranes can be facilitated by the introduction of cationic ammonium or phosphonium substituents (Figure 2 e and f). [ 42 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 ]…”