Catalysis

Intramolecular force

Enantioselective synthesis

Metallurgy

Materials science

Coupling (piping)

Receptor

Desymmetrization

Palladium

Biochemistry

Molecule

Stereochemistry

Polymer

Combinatorial chemistry

Ligand (biochemistry)

Organic chemistry

Fluorene

Calixarene

Chemistry

Chemical Science

Under the catalysis of PdBr2 and a chiral phosphoramidite ligand, the upper-rim mono (2-bromoaroyl)-substituted calix[4]arene derivatives underwent a facile enantioselective desymmetrization reaction to afford 9H-fluorene-embedded inherently chiral calixarenes in good yields with excellent enantioselectivities. The transannular dehydrogenative arene-arene coupling reaction proceeded most probably through an oxidative addition of the Caryl-Br bond to a ligated palladium catalyst followed by a sequence of an enantioselective 1,5-palladium migration and an intramolecular C-H arylation sequence. This new family of inherently chiral calixarenes possesses unique chiroptical properties thanks to their highly rigid structure induced by the 9H-fluorene segment.

Inherently chiral calixarenes by a catalytic enantioselective desymmetrizing cross-dehydrogenative coupling