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In Situ Grignard Metalation Method for the Synthesis of Hauser Bases
Author(s) -
Sengupta Simon,
Schüler Philipp,
Görls Helmar,
Liebing Phil,
Krieck Sven,
Westerhausen Matthias
Publication year - 2022
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202201359
Subject(s) - metalation , homoleptic , chemistry , yield (engineering) , solvent , amine gas treating , grignard reagent , reagent , salt (chemistry) , inorganic chemistry , organic chemistry , metal , materials science , metallurgy
The in situ Grignard Metalation Method ( i GMM) is a straightforward one‐pot procedure to quickly produce multigram amounts of Hauser bases R 2 N‐MgBr which are valuable and vastly used metalation reagents and novel electrolytes for magnesium batteries. During addition of bromoethane to a suspension of Mg metal and secondary amine at room temperature in an ethereal solvent, a smooth reaction yields R 2 N‐MgBr under evolution of ethane within a few hours. A Schlenk equilibrium is operative, interconverting the Hauser bases into their solvated homoleptic congeners Mg(NR 2 ) 2 and MgBr 2 depending on the solvent. Scope and preconditions are studied, and side reactions limiting the yield have been investigated. DOSY NMR experiments and X‐ray crystal structures of characteristic examples clarify aggregation in solution and the solid state.