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M. Schnürch:
"Byproduct Inspired Reaction Development";
Vortrag: 3rd CHAOS Meeting (COST), Bath (eingeladen); 18.09.2017 - 20.09.2017.

reactions. [1] An important reason for this is the increased atom efficiency, which bears the potential for overall more efficient
synthesis of valuable compounds. Many different reactions have been realized using C-H activation chemistry such as arylation,
amidation, alkenylation or alkylation, to name only a few. The latter method often relies on alkenes as the alkyl source, which
brings about a few limitations. [2],[3] Most importantly, short chained alkenes are gaseous and hence such reactions have to be
carried out using special equipment compatible with high pressures. So for the most simple alkylations (e.g. ethylation and
propylation), the most experimental effort is required.
Thinking about an operationally more simple protocol, we considered in situ formation of the olefine from a suitable substrate,
which should be crystalline at room temperature and only release the olefine in course of the reaction. The simple solution was
using quaternary ammonium salts, which form olefins via the well-known Hofmann elimination. [4],[5]
Within this contribution, the scope and limitations of this new methodology will be presented first on a model system. Additionally,
it will be demonstrated that quaternary ammonium salts can be used as alkyl source on a number of different substrates, using
various types of directing groups and metal catalysts. Hence, an easy to use, attractive, and interesting alternative alkylation
method to the use of olefins will be disclosed, which additionally shows considerably generality.

C-H activation, Hofmann elimination, quarternary ammonium salts, alkylation