Abstract
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(sp3)–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 β-C(sp3)–H arylation of propionic acid and related α-branched aliphatic acids giving access
to hydrocinnamic acids derivatives in a highly straightforward manner.
1 Introduction
2 Challenges in the C(sp3)–H Bond Activation of Carboxylic Acids
3 History/State of the Art
4 Studies towards a General β-C(sp3)–H Functionalization of Aliphatic Acids
5 Conclusion
Key words
C–H activation - carboxylic acids - arylation - palladium catalysis - propionic acid