An expeditious procedure for the synthesis of isotopically labelled fatty acids: preparation of 2,2-d2-nonadecanoic acid

We describe a new synthetic path for the preparation of isotopically labelled saturated odd-numbered fatty acids by a homologation procedure for the direct conversion of carboxylic acids into their 2,2-dideuterated homologues. This process can be used to obtain both odd- and even-numbered 2,2-dideuterated fatty acids starting from carboxylic acids. Furthermore, the reiteration of this process can also be used for the synthesis of polydeuterated fatty acids in which the heavy atoms are placed on adjacent carbon atoms or differently arranged in the molecule.