# Stable BF2 Boracycles as Versatile Reagents for Selective Ortho C–H Functionalization

## TL;DR

A new method for making stable BF2 boracycles is developed, enabling efficient and selective chemical modifications for pharmaceutical use.

## Contribution

A metal-free, scalable synthesis of stable BF2 boracycles is introduced, eliminating the need for chromatography.

## Key findings

- BF2 boracycles can be synthesized in multigram quantities without column chromatography.
- They enable ipso-substitution to produce halogenated, hydroxylated, and azidated derivatives.
- They show excellent reactivity in Suzuki–Miyaura cross-coupling reactions for C–C bond formation.

## Abstract

The development of new boron reagents continues to play a crucial role in advancing modern organic synthesis, particularly in C–H functionalization and cross‐coupling reactions. Herein, we report a metal‐free, robust, and scalable multigram protocol for the synthesis of stable BF2 boracycles that require no column chromatography, providing a practical and efficient route to access this valuable boron species. The BF2 boracycles exhibit enhanced stability and reactivity, making them highly versatile intermediates for late‐stage diversification. They undergo ipso‐substitution to afford a wide array of derivatives, including halogenated (e.g., radioiodinated), hydroxylated, and azidated products. Furthermore, they display excellent reactivity in Suzuki–Miyaura cross‐coupling reactions, enabling both C(sp2)─C(sp2) and C(sp2)─C(sp3) bond formation. These results underscore the utility of BF2 boracycles as powerful tools for selective functionalization in pharmaceutical synthesis and beyond. Our work represents a significant advancement in organoboron chemistry, offering both a streamlined synthetic approach and broad applicability for complex molecule construction.

We report a robust, metal‐free and scalable synthesis of stable BF2 boracycles via directed ortho CH borylation, delivering isolable, shelf‐stable reagents without chromatographic purification. These BF2 boracycles exhibit unique and tunable reactivity, enabling highly selective ipso‐functionalization across a broad range of transformations. Their exceptional stability, wide substrate scope, and superior reactivity establish BF2 boracycles as powerful alternatives to conventional organoboron reagents for pharmaceutical and radiochemical applications.