title: Nickel-Catalyzed Cyclopropanation with NMe4OTf and nBuLi.
abstract: Nickel was identified as a catalyst for the cyclopropanation of unactivated olefins by using in situ generated lithiomethyl trimethylammonium triflate as a methylene donor. A mechanistic hypothesis is proposed in which the generation of a reactive nickel carbene explains several interesting observations. Additionally, our findings shed light on a report by Franzen and Wittig published in 1960 that had been retracted later owing to irreproducibility, and provide a rational basis for the systematic development of the reaction for preparative purposes as an alternative to diazomethane or Simmons-Smith conditions.
authors.affiliation: Laboratorium für Organsiche Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich (Switzerland).
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Künzi
authors.affiliation: Laboratorium für Organsiche Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich (Switzerland).|Present address: ICIQ, Av. Països Catalan 16, 43007 Tarragona (Spain).
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Sarria Toro
authors.affiliation: Laboratorium für Organsiche Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich (Switzerland).|Present address: Institut für Technische und Makromol. Chemie, RWTH Aachen University, Worringerweg 1, 52075 Aachen (Germany).
authors.forename: Tim
authors.initials: T
authors.lastname: den Hartog
authors.affiliation: Laboratorium für Organsiche Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich (Switzerland). peter.chen@org.chem.ethz.ch.
authors.forename: Peter
authors.initials: P
authors.lastname: Chen
keywords: carbenes; cyclopropanation; nickel; ylides