Catalytic Enantioselective Synthesis of Conformationally Stable C(sp ² )−C(sp ³ ) Naphthocoumarin Atropisomers

A straightforward atroposelective access to enantiomerically enriched 2‐hydroxy‐3‐(2‐oxochroman‐4‐yi)naphthalene‐1,4‐diones (with yields ranging from 32% to 87% and enantiomeric excesses up to 99%) is described. Using an organocatalytic approach, 2‐hydroxynaphthoquinone reacts with a 3‐coumarin‐3‐carboxylic acid through a tandem 1,4‐addition/decarboxylation process initiated by a thiourea‐functionalized cinchona alkaloid, which efficiently controls the stereochemistry of a newly forged stereocenter, while simultaneously directing the formation of a configurationally stable C(sp 2 )−C(sp 3 ) synclinal atropisomer. The methodology has been explored across a broad substrate scope, and the results are supported by detailed nuclear magnetic resonance (NMR) analyses, single‐crystal X‐ray diffraction, and density functional theory (DFT) calculations.