Stille Coupling Catalyzed by Gold Nanoparticles Formed In Situ on Active Carbon
In Situ Generated Gold Nanoparticles on Active Carbon as Reusable Highly Efficient Catalysts for a C(sp3)–C(sp3) Stille Coupling.
Angew. Chem. Int. Ed. 2019;
17 September 2019 (online)
Key wordsgold catalysis - nanoparticles - Stille coupling - benzyl halides - allylstannanes - dienes
Activated-carbon-adsorbed gold nanoparticles formed in situ catalyzed the C(sp3)–C(sp3) coupling reaction of benzylic bromides with allyl(tributyl)stannanes to give the corresponding homoallylic benzenes in up to >99% yield (eq.1). This catalyst was also applicable on an allyl–allyl coupling reaction to furnish 1,5-dienes in yields of 54–59% (eq. 2).
The coupling of (2-bromoethyl)benzene with allyl(tributyl)stannane proceeded in the presence of a 0.001 mol% loading of the gold nanoparticles to give the coupling product in 29% yield with a total turnover number of up to 29000. The catalyst was recovered by centrifugation and recycled four times without a loss of its catalytic activity.