152952-99-3Relevant academic research and scientific papers
A Suzuki coupling based route to 2,2′-bis(2-indenyl)biphenyl derivatives
IJpeij, Edwin G.,Beijer, Felix H.,Arts, Henricus J.,Newton, Claire,De Vries, Johannes G.,Gruter, Gert-Jan M.
, p. 169 - 176 (2002)
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)4NOH 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.
