Aryltransfer

Aryltransfer refers to chemical reactions in which an aryl group (an aromatic ring, Ar) is transferred from a donor species to an acceptor, producing an arylated product. The term encompasses a range of processes that enable the formation of Ar–X bonds (where X is a variety of nucleophiles or coupling partners) by transferring a preformed aryl unit. Aryltransfer is a common strategic step in constructing biaryl frameworks and other aryl-containing compounds used in pharmaceuticals, agrochemicals, and materials science.

Mechanistic routes to aryl transfer vary with the reagents and conditions. Prominent aryl-transfer reagents include diaryliodonium and related hypervalent iodine(III) species, which can deliver an aryl group to nucleophiles or metal centers. Aryl transfer can proceed through ionic pathways, radical pathways, or metal-catalyzed mechanisms. In photoredox and radical chemistry, aryl diazonium salts serve as aryl donors that generate aryl radicals under light, enabling subsequent coupling steps. In transition-metal catalysis, cross-coupling paradigms such as nickel- and copper-catalyzed reactions can be viewed as aryl transfer steps where an aryl fragment is transmitted from a donor to a partner to form C–C or C–heteroatom bonds.

Applications of aryl transfer include the synthesis of biaryl compounds, aryl ethers, and other arylated products essential to drug discovery and materials development. Challenges in the field include achieving high regio- and chemoselectivity, expanding the scope of aryl donors, and developing milder, more sustainable conditions.