Recent advances in decarboxylative C-C bond formation using direct or in situ generated alkenyl acids

ABSTRACT

In recent years, the reactions of abundantly available, inexpensive, and structurally diverse alkenyl acids (-C=C-COOH) with C-X (X = halogen) or C-H coupling partner have emerged as vital strategies for the streamlined synthesis of functionalized alkenes with extrusion of innocuous CO₂. Various alkenyl acids such as cinnamic acids can act as stable surrogates for the polymerization prone styrenes/olefins, which otherwise need special attention for their handling and storage. Furthermore, cinnamic acids can be easily prepared through various methodologies including Knoevenagel-Doebner (KD) condensation, Heck coupling reaction, etc. Recently, various one-pot tandem methodologies involving the decarboxylative coupling of KD/Heck sequence with C-H or C-X substrate have come into fore. The present review article edifies about the recent advances, scope and limitations for C-C bond formation via (i) direct decarboxylative functionalization of C-X or C-H substrate with alkenyl acids, (ii) tandem one-pot multicomponent decarboxylative approaches (involving in situ generated alkenyl acids) e.g. coupling of KD/Heck sequences with C-X or C-H substrate.

Graphical abstract

Acknowledgments

The authors (RK) wish to thank the Department of Science and Technology, New Delhi for the financial support (SB/FT/CS-108/2013) and Central University of Punjab, Bathinda, for internal RSM grant. PK is thankful to Department of Science and Technology for DST INSPIRE Fellowship (DST/INSPIRE Fellowship/2016/IF 160705).

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Funding

This work was supported by the Department of Science and Technology New Delhi [EMR/2015/002339].