gammaalkylationarylation

Gammaalkylationarylation is a descriptor used in some chemical discussions to refer to a class of tandem or cooperative transformations that aim to install an alkyl group at the gamma position of a substrate while simultaneously introducing an aryl group. The gamma position is typically defined as the carbon three bonds away from a functional group such as a carbonyl, an imine, or a heteroatom. In this framing, the aryl moiety is added at a defined site by cross-coupling, radical aryl transfer, or related arylation chemistry, while the gamma-alkylation occurs through radical, ionic, or organometallic pathways.

Mechanistically, gammaalkylationarylation often employs dual or cooperative catalysis. Common approaches include photoredox catalysis paired with nickel or palladium catalysis to generate and couple radical and organometallic intermediates within a single pot. A typical sequence might involve generation of an alkyl radical that adds to a pi-system at the gamma position of an enone or similar substrate, followed by an arylation event that installs an aryl group either through a cross-coupling step or a radical–polar crossover, yielding densely functionalized products in one operation or in a concise cascade.

Substrates of interest include enones, acrylamides, and related alkenyl carbonyl compounds, with alkyl radical sources such as alkyl boronates, alkyl halides, or other radical precursors, and aryl sources including aryl halides or arylboron reagents. Catalysts commonly cited encompass nickel, palladium, or copper systems in combination with photoredox catalysts or Lewis acids, along with suitable ligands.

The term is not universally standardized in the literature; many related transformations are discussed separately as gamma-alkylation and arylation or as cascade cross-couplings. When used, gammaalkylationarylation highlights a concerted or sequential integration of gamma-alkylation and arylation events to rapidly assemble complex, densely substituted frameworks.