Enantioselective (8+3) Cycloadditions by Activation of Donor–Acceptor Cyclopropanes Employing Chiral Brønsted Base Catalysis

Abstract A novel enantioselective (8+3) cycloaddition between donor–acceptor cyclopropanes and heptafulvenoids catalysed by a chiral bifunctional Brønsted base is described. Importantly, the reaction, which leverages an anionic activation strategy, divergent from prototypical Lewis‐acid protocols. series of cyclopropylketones react with tropones affording desired cycloadducts in high yield enantiomeric excess. For barbiturate substituted heptafulvenes, proceeds good yield, excellent diastereoselectivity The experimental work supported DFT calculations, indicate that organocatalyst activates both cyclopropane tropone; reaction step‐wise manner ring‐closure being stereodetermining step.