Exclusive 5-exo-dig hydroarylation of o-alkynyl biaryls proceeding via C-H activation pathway.
The first example of the palladium-catalyzed exclusive 5-exo-dig hydroarylation of o-alkynyl biaryls has been demonstrated. In contrast to the reported earlier carbocyclizations proceeding via the Friedel-Crafts mechanism, this hydroarylation efficiently proceeds with electron-neutral and electron-deficient arenes, producing fluorene frameworks with defined stereochemistry of the double bond. On the basis of the high reactivity of electron-deficient arenes toward cyclization, high values of inter- and intramolecular kinetic isotope effects, and the exclusive cis-selectivity of cyclization, a mechanism involving a C-H activation motif has been proposed for this transformation.
Chernyak
Natalia
N
Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
Gevorgyan
Vladimir
V
D000480:Alkynes / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D005449:Fluorenes / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D008956:Models, Chemical; D010165:Palladium / Q000737:chemistry*; D011084:Polycyclic Aromatic Hydrocarbons / Q000138:chemical synthesis*
D000480:Alkynes; D005449:Fluorenes; D011084:Polycyclic Aromatic Hydrocarbons; C041509:fluorene; D010165:Palladium; D002244:Carbon; D006859:Hydrogen