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.
Cabua et al. (Tue,) studied this question.