The Direct Pd-Catalyzed -C(sp 3 )-H Activation of Carboxylic Acids

The carboxylic acid moiety is one of the most versatile and abundant functional groups. However, despite of tremendous progress in the field of C-H functionalization reactions its use as a directing group for C(sp (3) )-H activation has remained limited. In this Synpact article we present the challenges associated with the carboxylic acid moiety as a native directing group and report on the newest developments in this field, including our recent study in which we developed a generally applicable protocol for the direct palladium catalyzed -C(sp (3) )-H arylation of propionic acid and related -branched aliphatic acids giving access to hydrocinnamic acids derivatives in a highly straightforward manner. 1Introduction 2Challenges in the C(sp (3) )-H Bond Activation of Carboxylic Acids 3History/State of the Art 4Studies towards a General -C(sp (3) )-H Functionalization of Aliphatic Acids 5Conclusion