Novel synthetic methodologies based on carbon dioxide: alpha-amino acid derivatives from nitrone umpolung, an atom-economic process, catalysed by transition metals

点击翻译按钮获取中文摘要

The chemical recycling of CO2 would provide a cheap, non toxic, and abundant carbon source for chemical industries. Therefore, there is a need for chemists to develop novel methodologies that use CO2 as a C1 building-block, despite its poor intrinsic reactivity. We aim to participate in this challenge through the proposed original approach for the synthesis of α-amino acid derivatives from nitrones and CO2. Nitrones are stable, easy to manipulate intermediates, which are readily available from a large variety of carbonyl compounds. Consequently, the scope of this reaction is potentially broad as it could give access to highly diverse α-amino acid derivatives, including α-N-hydroxyamino acids and α, α-disubstituted amino acids. The latter are highly valuable building blocks for pharmaceutical research. Should this project be successful, the developed synthetic method would be highly attractive compared to the current processes for preparing α-amino acids and would contribute to the valorisation of CO2 as a feedstock for chemical industries.Our project stems from the recent discovery of the SmI2-promoted nitrone umpolung in Grenoble and its success will depend strongly on our capacity to find appropriate conditions for reaction of the resulting intermediates with CO2. The expertise of the Karlsruhe chemists in the use and activation of CO2 will thus be essential for the achievement of this program’s objectives. While the partners in Grenoble will input their competence in the field of nitrone umpolung for scope, limitations, mechanistic and stereochemical aspects, the role of the partners in Karlsruhe will be to delineate the optimal conditions for performing the reactions with CO2 in terms of temperature, pressure, and possibly activation by transition metals. Once the feasibility of the reaction is demonstrated, research will focus on avoiding the use of excess SmI2, in order to translate this process into an economical and environmentally sustainable one.