A new Suzuki-Heck-type coupling cascade: Indeno[1,2,3]-annelation of polycyclic aromatic hydrocarbons

Under palladium catalysis, o-bromobenzeneboronic acid can be coupled with 1-bromonaphthalene (6) and with oligocyclic bromoarenes to furnish indeno-annelated polycyclic aromatic hydrocarbons 1-4 and 25 in a single operation in moderate to good yields (27-87%). Alternatively, o-dibromoarenes and 1,2-dibromocycloalkenes can be cross-coupled with 1-naphthaleneboronic acid under the same conditions to yield analogous products (6-87%), and indenocorannulene (19) can be prepared likewise in a single step from pinacol corannuleneboronate (18) (40%).