Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides

• Mateo Berton,
• Kevin Sheehan,
• Andrea Adamo and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115

• fresh organomagnesium reagents on a discovery scale and will do so independent from the operator’s experience in flow and/or organometallic chemistry. Keywords: Knochel–Hauser base; lithium chloride; magnesium; on-demand; packed-bed reactors; plug and flow reactor; synthesizer; turbo Grignard reagent

• reutilization. For optimal results, 2 equivalents of Mg* (chips/powder, 1:1) and 2 equivalents of LiCl must be used at a single time. System scope: The bicomponent column was employed to obtain the turbo Grignard reagent [45] as well as sec- and n-butylmagnesium chloride–lithium chloride complexes as THF

• solutions (≈10 mL). Very good yields were obtained: iPrMgCl⋅LiCl 2.19 M (88%); s-BuMgCl⋅LiCl 2.15 M (86%), and n-BuMgCl⋅LiCl (2.13 M, 85%, Table 2, entries 2–4). The formation of the turbo Grignard reagent (iPrMgCl⋅LiCl) was scaled up to ≈100 mmol using a 15 × 100 mm column, and the results were compared

Meta-metallation of N,N-dimethylaniline: Contrasting direct sodium-mediated zincation with indirect sodiation-dialkylzinc co-complexation

• David R. Armstrong,
• Liam Balloch,
• Eva Hevia,
• Alan R. Kennedy,
• Robert E. Mulvey,
• Charles T. O'Hara and
• Stuart D. Robertson

Beilstein J. Org. Chem. 2011, 7, 1234–1248, doi:10.3762/bjoc.7.144

• different components. The work of Knochel uncovered a special reactivity and selectivity that can be realised with a mixed lithium halide–magnesium amide complex sometimes labelled a “turbo-Grignard” reagent [8]. It has been proposed that LiCl breaks up the magnesium amide aggregates allowing more soluble