A Suzuki Coupling Based Route to 2,2‘-Bis(2-indenyl)biphenyl Derivatives

• Published in: Journal of organic chemistry Vol. 67; no. 1; pp. 169 - 176
• Main Authors: IJpeij, Edwin G, Beijer, Felix H, Arts, Henricus J, Newton, Claire, de Vries, Johannes G, Gruter, Gert-Jan M
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 11.01.2002; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Organic; Exact sciences and technology; Noncondensed benzenic compounds; Organic chemistry; Physical Sciences; Preparations and properties; Science & Technology; REAGENTS; POLYPROPYLENE; STRATEGY; ZIRCONOCENE CATALYSTS; COMPLEXES; POLYMERIZATION; PROPYLENE; AROMATICS; METALLOCENE; ARYLBORONIC ACIDS; Solvent effect; Suzuki coupling; Catalytic reaction; Biphenyl derivatives; Toluene; Palladium complex; Aromatic compound; Indene derivatives; Chemical synthesis; Boronic acids; Methanol
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo016040i

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.