Cooperative N-heterocyclic carbene (NHC)–Lewis acid-mediated regioselective umpolung formal [3 + 2] annulations of alkynyl aldehydes with isatins

Abstract

A novel and regioselective umpolung synthesis of spirooxindoles has been developed by cooperative NHC-Lewis acid-mediated formal [3 + 2] annulations of alkynyl aldehydes with isatins. In most cases, the reactions proceeded via a(3)-d(3) umpolung of alkynyl aldehydes resulting in spirooxindole butenolides. In a few cases, spirooxindole furan-3(2H)-ones were formed as the major products via an a(1)-d(1) umpolung process by controlling the reaction temperature. These newly formed spirooxindoles could provide promising candidates for chemical biology and drug lead discovery.

The Synthesis of New Spirolactones from Substituted Isatins

“…The O2-C9 =1.353(2)Å and O2-C2=1.453(2) Å distances differ due to different hybridization of bonded carbon atoms. The compound exhibits structural similarities with an already reported related structure [33][34][35][36]. Thus the major component in reaction of N-ethyl isatin 3, dimethyl acetylenedicarboxylate and triphenylphosphine could be formulated as 4.…”

Synthesis and characterization of MgO nanoparticles supported on ionic liquid‐based periodic mesoporous organosilica (MgO@PMO‐IL) as a highly efficient and reusable nanocatalyst for the synthesis of novel spirooxindole‐furan derivatives

“…Synthesis of spirooxindole‐furan derivatives has been performed through the interrupted Feist–Benary reaction (IFB) under homogeneous conditions in the presence of organic and inorganic base catalysts, such as K 2 CO 3 , DBU, DABCO, DIPEA and NEt 3. However, these methods suffer from some disadvantages, including toxicity and expensiveness, difficult work‐up and catalyst recovery processes, long reaction times, low reaction yields, high amounts of catalyst, and non‐ecofriendly reaction conditions . To overcome these problems, recently some recoverable heterogeneous catalysts have been developed …”

Kooperative Katalyse mit N‐heterocyclischen Carbenen

“…[19] Die Reaktion von Inalen und Isatinen in Gegenwart von NHCs ergab Gemische von Produkten einer Allenolat-Addition oder einer Acylanion-Addition. [19] Die Reaktion von Inalen und Isatinen in Gegenwart von NHCs ergab Gemische von Produkten einer Allenolat-Addition oder einer Acylanion-Addition.…”