title: A Suzuki coupling based route to 2,2'-bis(2-indenyl)biphenyl derivatives.
abstract: Because of the promising performance in olefin polymerization of 2,2'-bis(2-indenyldiyl)biphenyl zirconium dichloride, we developed a new and broadly applicable route to 2,2'-bis(2-indenyl)biphenyl derivatives. Reaction of the known 2,2'-diiodobiphenyl (26) with the new 2-indenyl boronic acid (23) did not result in the desired 2,2'-bis(2-indenyl)biphenyl (10); instead an isomer thereof, (spiro-1,1-(2,2'-biphenyl)-2-(2-indenyl)indane) (27), was obtained. It was found that compound 10 could be made via a palladium-catalyzed reaction of 2,2-biphenyldiboronic acid (31) with 2-bromoindene (21) under standard Suzuki reaction conditions. However, the yield of this reaction was low at low palladium catalyst loadings, due to a competitive hydrolysis reaction of 2,2-biphenyldiboronic acid (31). HTE techniques were used to find an economically viable protocol. Thus, use of the commercially available 1.0 molar solution of (n-Bu)(4)NOH in methanol with cosolvent toluene led to precipitation of the pure product in a fast and clean reaction, using only 0.7 mol % (0.35 mol % per C-C) of the expensive palladium catalyst.
authors.affiliation: DSM Research, Department of Polyolefins, Chemistry and Catalysis, P.O. Box 18, 6160 MD Geleen, The Netherlands. Edwin.ijpeij@dsm.com
authors.forename: Edwin G
authors.initials: EG
authors.lastname: IJpeij
authors.forename: Felix H
authors.initials: FH
authors.lastname: Beijer
authors.forename: Henricus J
authors.initials: HJ
authors.lastname: Arts
authors.forename: Claire
authors.initials: C
authors.lastname: Newton
authors.forename: Johannes G
authors.initials: JG
authors.lastname: de Vries
authors.forename: Gert-Jan M
authors.initials: GJ
authors.lastname: Gruter