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M. Schnürch, D. Schönbauer, F. Lukas:
"Toluene and derivatives as new and appealing N-benzylation reagents replacing classical benzyl halides";
Poster: BOSS XVI, 16th Belgian Organic Synthesis Symposium, Brüssel; 08.07.2018 - 13.07.2018; in: "BOSS XVI - Programme and Book of Abstracts", (2018), S. P240.

Toluene as a replacement for common N - benzylating agents such as benzyl bromide can be an attractive alternative for different benzylation reactions such as C- or N-benzylation. The advantage of toluene derivatives is the much better atom efficiency, since formally only H2 is created as waste instead of HX (X = Cl, Br), which requires an additional neutralization step.
Within this research project, an N-benzylation protocol under nickel catalysis and mildly oxidative conditions was developed using different N-alkylated 2-aminopyridines as starting materials. The pyridine group acts as directing group. The developed process is not limited to simple toluene, but also substituted derivatives can be applied giving the desired product in good yields.
Additionally, cleavage of the pyridine directing group to unsymmetrically substituted secondary amines is also demonstrated. Furthermore, a comparison of the reaction profiles between the beforehand described method and using conventional benzyl bromide as electrophile is shown.