Over the last decade, substantial research has led to the introduction of an impressive number of efficient procedures which allow the selective construction of CC bonds by directly connecting two different CH bonds under oxidative conditions. Common to these methodologies is the generation of the reactive intermediates in situ by activation of both CH bonds. This strategy was introduced by the group of Li as cross-dehydrogenative coupling (CDC) and discloses waste-minimized synthetic alternatives to classic coupling procedures which rely on the use of prefunctionalized starting materials. This Review highlights the recent progress in the field of cross-dehydrogenative C sp 3C formations and provides a comprehensive overview on existing procedures and employed methodologies.

The transition-metal-catalyzed amination of aryl halides has been the most powerful method for the formation of aryl amines over the past decades. Phenols are regarded as ideal alternatives to aryl halides as coupling partners in cross-couplings. An efficient palladium-catalyzed formal cross-coupling of phenols with various amines and anilines has now been developed. A variety of substituted phenols were compatible with the standard reaction conditions. Secondary and tertiary aryl amines could thus be synthesized in moderate to excellent yields.

Aryl ethers are ubiquitous compounds and intermediates widely used in the synthesis of dyes, cosmetics, materials, fragrances, plant protection agents, stabilizers for plastics, natural products, and pharmaceuticals. [1] Within these molecules, the ether functionality confers particular properties to the aromatic ring. The ability to synthesize aryl ethers with a wide range of aliphatic and aromatic moieties represents a challenge and has thus attracted constant interest throughout the history of organic chemistry. Nevertheless, all existing methods for the preparation of aromatic ethers are based on the same reaction schemes, starting from aromatic precursors, either with a pre-existing oxygen atom (phenols) or with a pre-installed reactive functionality (Scheme 1, left). For example, aryl alkyl ethers can be prepared by nucleophilic substitution reactions of either a phenol with an aliphatic substrate (Williamson reaction), [2,3] or of an alcohol with an aromatic precursor. [4] In the same manner, other approaches have been developed more recently, such as transition-metalcatalyzed allylic O alkylation reactions of phenols, electrophilic addition reactions of phenols to alkenes, [5] coupling reactions between alcohols and aryl halides through palladium (Buchwald-Hartwig reaction) [6] or copper (Ullmann ether synthesis) [7,8] catalysis, and copper-catalyzed coupling reactions of alcohols with arylboron (Chan-Lam type coupling) [9] or arylbismuth [10] compounds, but all these approaches still require aromatic substrates. In addition, stoichiometric amounts of unwanted by-products are gener-Scheme 1. General approaches for the preparation of aryl ethers [*] Dr.

Pd-catalyzed intermolecular aerobic dehydrogenative aromatizations have been developed for the arylation of amines with nonaromatic ketones. Under optimized reaction conditions, primary and secondary amines are selectively arylated in good yields with cyclohexanones and 2-cyclohexen-1-ones in the presence of a Pd-catalyst under an atmosphere of molecular oxygen.