A Route to Highly Functionalized β-Enaminoesters via a Domino Ring-Opening Cyclization/Decarboxylative Tautomerization Sequence of Donor–Acceptor Cyclopropanes with Substituted Malononitriles

An unprecedented and domino synthetic strategy for the synthesis of highly functionalized carbocyclic β-enaminoesters bearing an all-carbon quaternary center via Yb(OTf)3-catalyzed ring-opening cyclization/decarboxylative tautomerization of donor–acceptor cyclopropanes with 2-alkyl malononitriles in excellent yields is described. The products are obtained as a single diastereomer in most cases where the nitrile and aryl groups are aligning in a cis orientation across the ring.