“…Unlike other reviews for similar means, the purpose of this article is to focus on the most recent advances for preparing carboxylic acid derivatives from unsaturated hydrocarbon backbones using Ni as well as the cheaper and more abundant Fe species in a homogeneous 45 Page 2 of 38 Top Curr Chem (Z) (2016) 374:45 manner, including mechanistic considerations, when appropriate. Therefore, other catalytic CO 2 functionalization processes of paramount importance such as the area of cyclic carbonates [19][20][21], polymer formation, production of methanol or formic acid [22][23][24], electrochemical methods [25], co-catalyzed carboxylations [26], carbonylation methods [27], or reductive carboxylations of organic (pseudo)halides [14-16, 28, 29], among others, are beyond the scope of this review.…”