# Mallory-Type Reactivity of 1,2-Dihydroazaborinines: 6π-Electrocyclization-[1,5]‑H Shift Cascade toward BN-Doped Polycyclic Frameworks

## TL;DR

This paper explores the unique chemical reactions of 1,2-dihydroazaborinines to form BN-doped polycyclic frameworks through a cascade of photochemical processes.

## Contribution

The study introduces a novel cascade reaction involving 6π-electrocyclization and [1,5]-hydrogen shift to selectively synthesize BN-doped polycyclic frameworks.

## Key findings

- 1,2-Dihydroazaborinines undergo photochemistry to form Dewar or benzvalene isomers depending on substitution.
- An o-BN-terphenyl framework forms via 6π-electrocyclization and rearomatizes through a [1,5]-hydrogen shift.
- Oxidative conditions yield a BN-incorporated triphenylene, demonstrating selective synthesis of BN-doped frameworks.

## Abstract

1,2-Dihydro-1,2-azaborinines
exhibit highly selective substitution-dependent
photochemistry, yielding either Dewar or benzvalene isomers. Through
targeted substitution, an o-BN-terphenyl framework is constructed,
which undergoes 6π-electrocyclization upon irradiation. The
resulting BN-polyenes rearomatize spontaneously via a [1,5]-hydrogen
shift. Under oxidative conditions, an unprecedented BN incorporated
triphenylene results. By rationally tuning substitution and reaction
conditions, this pathway is favored over Dewar isomer formation, offering
selective routes to BN-doped polycyclic frameworks from multiphotoresponsive
precursors.