title: Combining Neopentyllithium with Potassium tert-Butoxide: Formation of an Alkane-Soluble Lochmann-Schlosser Superbase.
abstract: Mixtures of alkyllithium and heavier alkali-metal alkoxides are often used to form alkyl compounds of heavier alkali metals, but these mixtures are also known for their high reactivity in deprotonative metalation reactions. These organometallic mixtures are often called LiC-KOR superbases, but despite many efforts their constitution remains unknown. Herein we present mixed alkali-metal alkyl/alkoxy compounds produced by reaction of neopentyllithium with potassium tert-butoxide. The key to success was the good solubility and temperature-stability of neopentyl alkali-metal compounds, leading to hexane-soluble mixtures, which allowed handling at ambient temperatures and isolation by crystallization. The compounds in solid state and in solution were identified by X-ray crystallography and NMR spectroscopy as mixtures of lithium/potassium neopentyl/tert-butoxy aggregates of varying compositions Lix Ky Npz (OtBu)x+y-z .
authors.affiliation: Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128, Mainz, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Benrath
authors.affiliation: Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128, Mainz, Germany.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Kaiser
authors.affiliation: Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128, Mainz, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Limbach
authors.affiliation: Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128, Mainz, Germany.
authors.forename: Mihail
authors.initials: M
authors.lastname: Mondeshki
authors.affiliation: Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128, Mainz, Germany. klettj@uni-mainz.de.
authors.forename: Jan
authors.identifier: 0000-0002-0055-5335
authors.initials: J
authors.lastname: Klett
keywords: alkali metals; alkoxy groups; carbanions; lithium; superbases