Preparation of Functionalized Diaryl- and Diheteroaryllanthanum Reagents by Fast Halogen-Lanthanum Exchange
作者:Andreas D. Benischke、Lucile Anthore-Dalion、Guillaume Berionni、Paul Knochel
DOI:10.1002/anie.201709553
日期:2017.12.18
Aryl and heteroaryl halides (X=Br, I) undergo a fast and convenient halogen–lanthanum exchange with nBu2LaMe, which leads to functionalized diaryl‐ and diheteroaryllanthanum derivatives. Subsequent trapping reactions with selected electrophiles, such as ketones, aldehydes, or amides, proceeded smoothly at −50 °C in THF, affording polyfunctionalized alcohols and carbonyl derivatives. Kinetic competition
Tritylium assisted iodine catalysis for the synthesis of unsymmetrical triarylmethanes
作者:Thibaut Courant、Marine Lombard、Dina V. Boyarskaya、Luc Neuville、Géraldine Masson
DOI:10.1039/d0ob01502d
日期:——
The combined Lewis acid catalytic system, generated from molecular iodine and tritylium tetrafluoroborate effectively catalyzed the Friedel–Crafts (FC) arylation of diarylmethyl sulfides providing an efficient access to various unsymmetrical triarylmethanes. The addition of tritylium and iodine created a more active catalytic system to promote the cleavage of sulfidic C–S bonds.