Many synthetic routes to 2-acetyl-1-pyrroline have been described in the literature [9,31–36]. However, all of them suffer of the difficulty to be effectively transposed to an isotopic
labelling strategy because of long, fastidious and/or costly synthetic protocols. For instance, Schieberle and Grosch [12] realized directly the ring-deuteration of 2-acetylpyrrole in an autoclave by using deuterium gas, following a strategy of synthesis of the secondary alcohol as precursor of the labelled 2-acetyl-1-pyrroline. The deuteration was unfortunately incomplete, since the incorporation of deuterium atoms was comprised between 2 and 5.