Navigating Scholl-Type Oxidative Coupling: An Electronic Programming Toward Path Revelation, Selectivity, and Control

Scholl-type oxidative aryl-aryl coupling is a powerful strategy for constructing extended π-systems, yet achieving regioselectivity and stepwise control remains a formidable challenge. Here, we report a systematic study on tetraarylthiophene (TAT) frameworks, revealing how subtle electronic effects of aryl substituents govern C─C bond formation efficiency, selectivity, and pathways. Guided by electrochemical potentials and Hammett σ_p constants, we establish a reactivity trend-OMe > Me > ^tBu > H > Ph > F > Cl > CHO > CF₃-revealing that electron-rich aryls promote efficient coupling, while electron-deficient groups suppress reactivity. Crucially, face-selective mono-cyclization products (PTs) are achieved by electronic step discrimination, where strategically pairing electronically distinct aryls steers homo- versus cross-coupling outcomes, enabling precise control over sequential couplings. Our findings unveil a simple yet powerful electronic map to predict coupling outcomes, product evolution, and opens a rational path to design regioselective oxidative cyclizations in polyaryl architectures toward precise π-frameworks.