Preparation of Highly Reactive Lithium Metal Dendrites for the Synthesis of Organolithium Reagents

Abstract

A long-standing problem in the area of organolithium chemistry has been the need for a highly reactive Li-metal source that mimics Li-powders but has the advantage of being freshly prepared from inexpensive and readily available Li-sources. Here, we report a simple and convenient activation method using liquid ammonia that furnishes a new Li-metal source in the form of crystalline Li-dendrites. The Li-dendrites were shown to have ca. 100 times greater surface area than conventional Li-sources created by prototypical mechanical activation methods. Concomitant with the surface area increase, the Li-dendrites were shown to exhibit significant rate enhancements over Li-powders, which are currently the industry standard for the preparation of organolithium compounds. These features were leveraged for the reproducible synthesis of organolithium reagents over a range of common laboratory scales.

Breaking the tert-Butyllithium Contact Ion Pair: A Gateway to Alternate Selectivity in Lithiation Reactions

“…The t-BuLi isotopomer 46 was effectively synthesized through reductive metalation using our newly developed 6 Lidendrites and 13 C enriched (CH 3 ) 3 13 CCl 45 (Figure 7). 38 To provide insight into the aggregate structure and composition of the active lithiation species formed by combining phosphoramides with t-BuLi, a series of 6 Li, 31 P, and 13 C NMR spectroscopic experiments were performed by titrating HMPA (Reich's method) 9a into solutions of doubly isotopically enriched CIP-46. 4.2.1.…”

Trendbericht Anorganische Chemie 2023: Hauptgruppen

“…Die Dendriten eignen sich, um Organolithiumverbindungen herzustellen, und ebnen den Weg zu weiteren Anwendungen. 1) Auch für bekannte Alkalimetallverbindungen gibt es vielversprechende neue Anwendungen, wie die Arbeitsgruppen Plajer und Hevia zeigen. Erstgenannte berichtet von Lithiumbenzolat und Lithiumhexamethyldi silazid als hocheffektive Katalysatoren für Ringöffnungspolymerisationen, mit denen sich Poly(ester-alt-esteralt-trithiocarbonate) herstellen lassen.…”

Schlenk's Legacy—Methyllithium Put under Close Scrutiny

“…Organolithium compounds including methyllithium feature also cornerstones in organometallic chemistry as transmetalation reagents (Figure 1). [14–17] Here, as for organic transformations, the availability and use of pure organolithium reagents is considered beneficial if not essential [18] . Hard to separate LiX contaminations do not only affect reagent/catalyst design and elucidation but also have a marked effect on the crystallographic and nuclear magnetic resonance properties of the synthesized complexes, and hence any interpretations made.…”