Donor‐Acceptor Cyclopropanes: Activation Enabled by a Single, Vinylogous Acceptor
Nils L. Ahlburg, Oliver Hergert, Peter G. Jones, Daniel B. Werz
Abstract
A novel class of highly activated donor-acceptor cyclopropanes bearing only a single, vinylogous acceptor is presented. These strained moieties readily undergo cycloadditions with aldehydes, ketones, thioketones, nitriles, naphth-2-ols and various other substrates to yield the corresponding carbo- and heterocycles. Diastereocontrol can be achieved through the choice of catalyst (Brønsted or Lewis acid). The formation of tetrahydrofurans was shown to be highly enantiospecific when chiral cyclopropanes are employed. A series of mechanistic and kinetic experiments was conducted to elucidate a plausible catalytic cycle and to rationalize the stereochemical outcome.
Topics & Concepts
AcceptorChemistryYield (engineering)CatalysisLewis acids and basesBrønsted–Lowry acid–base theoryStereochemistryCombinatorial chemistryOrganic chemistryMaterials sciencePhysicsCondensed matter physicsMetallurgyCyclopropane Reaction MechanismsCatalytic Alkyne ReactionsAsymmetric Synthesis and Catalysis