crosscouplingreaktioner

Crosscouplingreaktioner, also known as cross-coupling reactions, are a class of organic reactions that form carbon–carbon bonds by joining two fragments under the influence of a transition-metal catalyst, typically palladium or nickel. One fragment is usually an organometallic nucleophile (such as organoboron, organotin, or organozinc reagents), and the other fragment is an electrophile (commonly an aryl, vinyl, or alkyl halide or pseudohalide). The catalytic cycle generally involves oxidative addition of the electrophile to the metal, transmetalation with the nucleophile, and reductive elimination to forge the new C–C bond and regenerate the catalyst.

Major variants include Suzuki–Miyaura coupling (boron reagents with aryl or vinyl halides), Negishi coupling (organozinc reagents with halides), Kumada coupling (Grignard reagents with halides), Stille coupling (organotin reagents with halides), Sonogashira coupling (terminal alkynes with aryl or vinyl halides, often with copper co-catalyst), and the Heck reaction (coupling of aryl or vinyl halides with alkenes). These reactions enable diverse carbon–carbon architectures, including biaryl, alkyl–aryl, and heteroaryl frameworks.

Applications and considerations: crosscouplingreaktioner are foundational in organic synthesis, widely used in the production of pharmaceuticals, agrochemicals, natural products, and advanced materials. They typically tolerate various functional groups but can require air- and moisture-sensitive catalysts, specific ligands, bases, and solvents. Recent advances include nickel catalysis as a cost-effective alternative, improved ligand design, and photoredox- or dual-catalysis strategies that broaden substrate scope and sustainability.