A General Approach to Highly Substituted 1,2-Azaborines via Borylative Benzannulation of Unsaturated Imines
Year: 2026
Type: preprint
Abstract: Highly substituted, monocyclic 1,2-azaborines could expand the chemical space available for benzene bioisosterism; however, their synthesis remains an unmet challenge. Here we report a general, modular, transition-metal-free strategy that couples unsaturated imines with dihaloboranes to construct diverse 1,2-azaborines through a borylative benzannulation pathway. This method provides efficient access to tetra-, penta-, and hexa-substituted azaborines, including fused, macrocyclic and heteroatom-substituted scaffolds. High chemoselectivity and convenient handling are achieved by developing well-defined quinoline-buffered borylation reagents. Post-functionalization at the boron and nitrogen positions of 1,2-azaborines, synthesis of a BN-isostere of xibornol, and access to isotopically enriched 10B-1,2-azaborines have been demonstrated.
Source: ChemRxiv
Institutions: University of Chicago, Eli Lilly (United States)
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7208712558