Immobilization of ethylene bis-indenyl ligands on functionalized silica gel

Facile Synthesis of 3-Arylindenes by HMPA-Promoted Direct Arylation of Indenes with Aryl Fluorides

“…In 2002, Nifant’ev et al reported a facile Pd-catalyzed direct arylation of indene with aryl iodides to afford a mixture of 2- and 3-arylindenes in a 4/1 ratio (Scheme a) . The conventional method for the preparation of 3-substituted indenes involves first formation of indenyl lithium, generated in situ by deprotonation of indene with n -butyl lithium and subsequently reaction with electrophiles (Scheme b–d) . This method suffers from several drawbacks, such as the use of very low temperatures, long reaction time, and unsatisfactory regioselectivity.…”