Transition metal-catalyzed direct functionalization of C–H bonds is one of the key emerging strategies that is currently attracting tremendous attention with the aim to provide alternative environmentally friendly and efficient ways for the construction of C–C and C–hetero bonds. In particular, the strategy involving regioselective C–H activation assisted by various functional groups shows high potential, and significant achievements have been made in both the development of novel reactions and the mechanistic study. In this review, we attempt to give an overview of the development of utilizing the functionalities as directing groups. The discussion is directed towards the use of different functional groups as directing groups for the construction of C–C and C–hetero bonds via C–H activation using various transition metal catalysts. The synthetic applications and mechanistic features of these transformations will be discussed, and the review is organized on the basis of the type of directing groups and the type of bond being formed or the catalyst.

Transition metal-catalyzed C–H bond functionalizations by the use of diverse directing groups

Synthetically useful functional groups, including ketones, amides, carbamates, carboxylic acids, aldehydes or ethers, have been identified as weakly coordinating directing groups in efficient ruthenium(II)-catalyzed CH functionalizations. This strategy set the stage for versatile CH bond olefinations, oxygenations, nitrogenations and oxidative alkyne annulations among others. Thereby, step-economical access to diversely decorated arenes and heteroarenes was provided in a sustainable fashion.

Weakly Coordinating Directing Groups for Ruthenium(II)‐ Catalyzed CH Activation

Coumarin heterocyclic derivatives: chemical synthesis and biological activity

Sulfoxides are capable of forming stable complexes with transition metals and there have been many comprehensive studies into their binding properties. However, the use of sulfoxides, particularly chiral sulfoxides, as ligands in transition metal catalysis is rather less well developed. This review aims to describe these catalytic studies and covers new developments that are showing very promising results and that have led to a renewed interest in this field.

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The emergence of sulfoxides as efficient ligands in transition metal catalysis.

All-carbon quaternary centers in natural products and medicinal chemistry: recent advances

1,3-Enynes containing allylic hydrogens cis to the alkyne function as three-carbon components in rhodium(III)-catalyzed, all-carbon [3+3] oxidative annulations to produce spirodialins. The proposed mechanism of these reactions involves the alkenyl-to-allyl 1,4-rhodium(III) migration.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/ange.201503978

All-Carbon [3+3] Oxidative Annulations of 1,3-Enynes by Rhodium(III)-Catalyzed C ? H Functionalization and 1,4-Migration

Enantioselective Rh(I)-catalyzed cyclization of arylboron compounds onto ketones.

Synthesis of Benzopyrans by Pd(II)- or Ru(II)-Catalyzed C–H Alkenylation of 2-Aryl-3-hydroxy-2-cyclohexenones

2-Aryl-3-hydroxy-2-cyclohexenones are shown to be competent substrates for palladium- and ruthenium-catalyzed C–H alkenylation reactions with terminal alkenes, providing, in most cases, benzopyrans.

Martin D. Wieczysty

Papers

All-Carbon [3+3] Oxidative Annulations of 1,3-Enynes by Rhodium(III)-Catalyzed C ? H Functionalization and 1,4-Migration

Enantioselective Rh(I)-catalyzed cyclization of arylboron compounds onto ketones.

Synthesis of Benzopyrans by Pd(II)- or Ru(II)-Catalyzed C–H Alkenylation of 2-Aryl-3-hydroxy-2-cyclohexenones

Synthesis of Benzopyrans by Pd(II)- or Ru(II)-Catalyzed C—H Alkenylation of 2-Aryl-3-hydroxy-2-cyclohexenones.

All-Carbon [3 + 3] Oxidative Annulations of 1,3-Enynes by Rhodium(III)-Catalyzed C—H Functionalization and 1,4-Migration.