Photochemical Synthesis of a Ladder Diborole: A New Boron‐Containing Conjugate Material

Abstract

Climbing the ladder: Reductive cyclization of alkynyl haloboranes lead to the bis-benzocycloborabutylidene rather than the expected ladder diborole, despite the former being much less thermodynamically favored. Photochemical conversion to the ladder diborole was, however, quite facile upon irradiation at 254 nm.

Synthesis and Reactivity of Cationic Boron Complexes Distorted by Pyridine‐based Pincer Ligands: Isolation of a Photochemical Hofmann–Martius‐type Intermediate

“…In conclusion, we report the synthesis of a family of cationic boron complexes and the first reactivity of any pincer-distorted boron complex. Photo-controlled structural transformations at three-coordinate boron are rare, [31] and 4 a-c are the only boron complexes which undergo CÀN bond cleavage concomitant with CÀC bond formation. The strategy used here, namely the in-plane distortion of the geometry at three-coordinate boron, may facilitate the future activation of other strong bonds, including perhaps intermolecular reactions.…”

Postfunctionalization of BN‐Embedded Polycyclic Aromatic Compounds for Fine‐Tuning of Their Molecular Properties

“…Boron-containing compounds are generally sensitivet o oxygen and moisture due to the electron deficiency of the boron atom. Therefore, bulky groups are usually required to kinetically stabilize the boron center, [9] but at the expense of preventings olid-state p-p stacking. Recently,i tw as demonstrated by Yamaguchi et al that enforced planarity could stabilize boron-containing p-conjugated materials by increasing the energy demando fc onformation change to the skeleton.…”

Borylated Dibenzoborepin: Synthesis by Skeletal Rearrangement and Photochromism Based on Bora‐Nazarov Cyclization

“…[7] During the course of our research, the first synthesis of this skeleton was achieved by Piers and co-workers using an elegant photoisomerization of bi(benzoboratacyclobutylidene). [8] Meanwhile, in our efforts to synthesize this skeleton, we unexpectedly obtained the 10-borylated dibenzoborepin 2 by an anomalous skeletal rearrangement. To our surprise, this compound showed dramatic photochromic properties.…”