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; turboGrignardreagent
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 turboGrignardreagent [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 turboGrignardreagent (iPrMgCl⋅LiCl) was scaled up to ≈100 mmol using a 15 × 100 mm column, and the results were compared
PDF
Graphical Abstract
Figure 1:
Comparing on-demand coffee and turbo Grignard pod-style machines.
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
PDF
Graphical Abstract
Scheme 1:
Proposed stepwise mechanism for the zincation of benzene.