Abstract

Frontier molecular orbital engineering provides a powerful means to control chemical reactivity and unlock new catalytic functions in main-group compounds. However, prevailing approaches largely rely on geometric distortion, a design principle that has proven highly successful for multivalent p-block centres, but remains poorly suited to divalent chalcogen systems owing to its element-specific nature. Here we introduce a conceptually distinct strategy that exploits through-space orbital interactions to tailor electronic structure in divalent organosulfur compounds. By anchoring four sulfur atoms to a single carbon centre, a spirocyclic scaffold enforces spatial overlap between sulfur p orbitals, giving rise to a four-centred highest-occupied molecular orbital of elevated energy. This design unveils a multicentred main-group catalyst that enables electrophilic arene halogenation with pronounced reactivity, distinguishing it from prototypical organosulfur compounds. Mechanistic studies reveal that multi-atom cooperativity co-localizes enhanced nucleophilicity in the sulfide state with unusual halogen-transfer capability in the corresponding sulfonium state. This catalytic platform is compatible with complex arenes that are otherwise difficult to functionalize and expands the toolkit for late-stage modification of drug-like scaffolds.

DOI: http://dx.doi.org/10.1038/s41929-026-01602-y